XI. LITERATURE AND HISTORY (part 5 of 5)

XI. LITERATURE AND HISTORY (part 5 of 5)

Twelve plates with, eight } without, lattice-plates. } With by-spines, 361. Dodecaspis. ------------------------------------------------------------------------- IV. Tribe Lychnaspida. Twenty radial spines all with lattice-plates (produced by union of the branched apophyses of each plate). ------------------------------------------------------------------------- Eighty parmal pores (four } No by-spines, 362. Tessaraspis. on each plate)--no coronal } pores in the plates. } With by-spines, 363. Lychnaspis.

One hundred and sixty to three } hundred or more parmal pores } No by-spines, 364. Icosaspis. (in each plate four aspinal } and four to twelve or more } With by-spines, 365. Hylaspis. coronal pores). }

{808}Subfamily 1. DIPORASPIDA, Haeckel.

Definition.--#Dorataspida# with twenty radial spines, each of which bears two opposite apophyses. The spherical shell is composed either of the meeting branches of these apophyses (Phractaspida), or of twenty perforated plates, produced by concrescence of their branches (Ceriaspida).

A. Tribe I. #Phractaspida#, Haeckel.

Definition.--#Dorataspida# without perforated plates; the spherical shell is composed only of the meeting branches of the two opposite apophyses, which arise from each radial spine. Therefore the meshes of the shell are all sutural.

Genus 349. Phractaspis,[389] Haeckel, 1881, Prodromus, p. 467.

Definition.--#Dorataspida# without perforated plates; shell composed only of the meeting branches of the two opposite apophyses, which arise from each radial spine. Condyles of the branch-ends without by-spines.

The genus Phractaspis is the most simple and primitive form among all Dorataspida, and may be regarded as the common ancestral form either of this whole family, or at least of its first subfamily, the Diporaspida. In all members of this subfamily the spherical shell is composed of twenty radial spines, each of which bears two opposite apophyses; but the mode of composition is different in the two tribes of the subfamily, in the Phractaspida and Ceriaspida. In the simpler tribe, the Phractaspida, the shell is composed only of the meeting branches of the apophyses of neighbouring spines; there are no peculiar perforated plates or shields. In the Ceriaspida, however, both apophyses of each single spine form a perforated plate or shield by union of their branches, and the shell is formed of the meeting edges of these shields. Of course the Ceriaspida must be derived from the simpler Phractaspida. Phractaspis, as the common ancestral form of both, exhibits a very simple structure of the shell (Pl. 137, figs. 1, 2). Commonly, if the fork-branches of each apophysis be not again branched, the shell possesses only twenty-two large meshes and forty sutures. More rarely their number increases, the fork-branches of the apophyses being again branched (Phractaspidium, Pl. 137, fig. 3).

Subgenus 1. Phractasparium, Haeckel.

Definition.--Shell with twenty-two meshes, and forty sutures, each spine with only four branches, its two apophyses being simply forked.

{809}1. Phractaspis prototypus, n. sp. (Pl. 137, fig. 2).

Radial spines cylindrical, thin, pointed; the outer and inner halves of nearly equal size. Each spine bears in its middle part two opposite apophyses, which are simply forked; the four condyles of each spine (or the thickened ends of the fork-branches) are united with the meeting condyles of the neighbouring spines by sutures. Therefore the network of the spherical shell is composed of twenty-two large meshes: two square polar meshes on each pole (a a a a and e e e e); eight triangular circumpolar meshes (each between two polar and one tropical spine, a b a and e d e); eight tropical rhomboidal meshes (each between one polar, one equatorial, and two tropical spines: a b c b and e d c d); and four rhomboidal equatorial meshes (each between two tropical and two equatorial spines c b c d).

Dimensions.--Diameter of the shell 0.1, of the meshes 0.03 to 0.04; breadth of the spines and bars 0.005.

Habitat.--Cosmopolitan; Mediterranean (Corfu), Atlantic (Stations 348, 354), Indian Ocean (Ceylon), Pacific (Stations 253, 265, 274), &c., surface.

2. Phractaspis complanata, n. sp. (Pl. 137, fig. 1).

Radial spines leaf-shaped, strongly compressed, two-edged, pointed; their outer part longer than the inner. Each spine with two opposite apophyses which are simply forked, therefore with four condyles. The network with forty sutures and twenty-two large meshes, as in the foregoing species. The broad faces of the eight polar spines lie in two meridian planes, of the four equatorial spines in the equatorial plane, of the eight tropical spines in two planes parallel to the latter. The planes of the leaf-shaped fork-branches lie in the spherical face.

Dimensions.--Diameter of the shell 0.1, of the meshes 0.02 to 0.03; breadth of the fork-branches 0.012.

Habitat.--South Atlantic, Station 343, surface.

3. Phractaspis condylophora, n. sp.

Radial spines quadrangular, thin; their outer pyramidal part shorter than the inner. Each spine with four branches, its two opposite apophyses being simply forked. The eighty condyles (or sutural ends of the branches) much thickened, twice to four times as broad as the branches themselves. Network with forty sutures and twenty-two large meshes, as in both foregoing species.

Dimensions.--Diameter of the shell 0.12, of the meshes 0.03 to 0.04; breadth of the condyles 0.01.

Habitat.--South Pacific, Station 288, surface.

4. Phractaspis bipennis, Haeckel.

Dorataspis bipennis, Haeckel, 1862, Monogr. d. Radiol., p. 413, Taf. xxi. figs. 1, 2.

Phractasplenium bipenne, Haeckel, 1882, Manuscript.

Radial spines very thin, quadrangular; their outer pyramidal part shorter than the inner. Each spine with four bent branches, its two opposite apophyses being simply forked. Eighty {810}condyles, very thin, pointed. In the specimens of this remarkable species, which I first observed in Messina, two opposite equatorial spines had quite free apophyses, not connected with the neighbouring spines; therefore the thin lattice-work of the shell exhibited only thirty-six sutures and twenty meshes (two meshes with six sutures, six meshes with four sutures, and twelve meshes with three sutures). In similar specimens, which I afterwards observed in the Canary Islands, all four equatorial spines were connected in the same manner with the neighbouring spines; therefore they possessed forty sutures and twenty-two meshes, like Phractaspis prototypus (Pl. 137, fig. 2). Perhaps the Mediterranean species represents a peculiar genus, Phractasplenium bipenne.

Dimensions.--Diameter of the shell 0.1, of the meshes 0.03 to 0.05; breadth of the spines 0.002.

Habitat.--Mediterranean (Messina), Canary Islands (Lanzerote), surface.

Subgenus 2. Phractaspidium, Haeckel.

Definition.--Shell with forty to eighty or more meshes, and eighty to one hundred or more sutures. Each spine with six to eight or more branches, its two apophyses being doubly forked or more ramified.

5. Phractaspis constricta, n. sp. (Pl. 137, fig. 3).

Radial spines strongly compressed, two-edged, pointed; their outer half twice constricted and somewhat longer than the inner half. Each spine with two opposite forked apophyses, the branches of which are again forked; therefore eight condyles on each spine. The network of the spherical shell with eighty sutures and sixty-two meshes (twenty-two large primary meshes and forty smaller secondary meshes, the latter between the distal fork-branches).

Dimensions.--Diameter of the shell 0.11, of the large meshes 0.04 to 0.05, of the small meshes 0.01; breadth of the spines 0.01.

Habitat.--South Atlantic, Station 348, depth 2450 fathoms.

6. Phractaspis cataphracta, Haeckel.

Acanthometra cataphracta, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 49, Taf. x. figs. 7, 8.

Dorataspis cataphracta, Haeckel, 1862, Monogr. d. Radiol., p. 415.

Radial spines thin, quadrangular; their outer pyramidal part shorter than the inner. Each spine with six to eight condyles, the fork-branches of their two opposite apophyses being (all or partly) again forked. The network with sixty to eighty sutures and meshes: sometimes as regular as in the preceding species, at other times more or less irregular.

Dimensions.--Diameter of the shell 0.1, of the meshes 0.02 to 0.04; breadth of the bars 0.004 to 0.008.

Habitat.--Mediterranean (Cette), Müller (Messina), Haeckel; North Atlantic, Station 353, surface.

{811}Genus 350. Pleuraspis,[390] Haeckel, 1881, Prodromus, p. 467.

Definition.--#Dorataspida# without perforated plates; shell composed only of the meeting branches of the two opposite apophyses, which arise from each radial spine. Condyles of the branch ends bearing by-spines.

The genus Pleuraspis has quite the same structure of the shell as the foregoing Phractaspis, and differs from it only in the development of external by-spines; commonly each condyle of the branch end of the apophyses bears one zigzag by-spine, which is directed parallel to the radial main-spine from which the apophyses arise. Therefore each suture of the shell is armed with two divergent by-spines (Pl. 137, fig. 4).

Subgenus 1. Pleurasparium, Haeckel.

Definition.--Shell regularly developed with twenty-two meshes and forty sutures (sometimes twenty to twenty-four meshes and thirty-six to forty-eight sutures); each spine commonly with four branches, its two apophyses being simply forked.

1. Pleuraspis horrida, n. sp. (Pl. 137, fig. 4).

Radial spines roundish, somewhat compressed, very thick, conical, pointed at both ends, outer part nearly twice as long as the inner. Two apophyses of each spine simply forked, with short and broad branches and thickened condyles. Forty sutures, very broad. Twenty-two large meshes three to four times as broad as the bars. By-spines much developed, as long as the radius, zigzag, with alternating recurved hooks.

Dimensions.--Diameter of the shell 0.15, of the meshes 0.04 to 0.06; breadth of the bars 0.01 to 0.015.

Habitat.--Tropical Pacific (east of Philippines), Station 215, surface.

2. Pleuraspis amphithecta, n. sp.

Radial spines two-edged, leaf-shaped, strongly compressed, pointed at both ends; outer half longer than the inner. Two apophyses of each spine simply forked, with short and very broad branches; condyles not thickened. Forty sutures, broad. Twenty-two large meshes twice to three times as broad as the bars. By-spines zigzag, half as long as the radius. (Resembles Phractaspis complanata, Pl. 137, fig. 1.)

Dimensions.--Diameter of the shell 0.12, of the meshes 0.02 to 0.03; bars 0.012.

Habitat.--Central Pacific, Station 274, surface.

{812}3. Pleuraspis costata, Haeckel.

Acanthometra costata, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 49, Taf. ii. fig. 1, Taf. x. figs. 4-6.

Dorataspis costata, Haeckel, 1862, Monogr. d. Radiol., p. 414, Taf. xxiii. fig. 1.

Radial spines roundish, conical, pointed at both ends; outer and inner halves of nearly equal length. Two apophyses of each spine simply forked, with broad branches and thickened condyles. Forty sutures, broad. Twenty-two large meshes, four to five times as broad as the bars. By-spines straight, denticulate, half as long as the radius. (This common species is rather variable in size and details.)

Dimensions.--Diameter of the shell 0.1 to 0.13, meshes 0.03 to 0.06, bars 0.005 to 0.01.

Habitat.--Cosmopolitan; Mediterranean, Atlantic, Pacific, surface.

4. Pleuraspis pyramidalis, n. sp.

Radial spines quadrangular, their outer part pyramidal, very thick, about half as long as the prismatic inner part. Two apophyses of each spine simply forked, with very short and broad branches. Condyles much thickened. Forty sutures, very broad. Twenty-two meshes small, the largest twice as broad as the bars; the smaller only half as broad. By-spines short, straight, denticulate, half as long as the radius.

Dimensions.--Diameter of the shell 0.14, meshes 0.005 to 0.03.

Habitat.--Western Tropical Pacific, Station 222, surface.

Subgenus 2. Pleuraspidium, Haeckel.

Definition.--Shell with forty to eighty or more meshes and eighty to one hundred or more sutures; each spine with six to eight or more branches, its two apophyses being forked twice or oftener.

5. Pleuraspis ramosa, n. sp.

Radial spines roundish, stout, somewhat compressed; their inner and outer half nearly of equal length. Two apophyses of each spine doubly forked or more irregularly branched; therefore commonly eight (sometimes six, seven, nine, or ten to twelve) thickened condyles on each spine. Sutures eighty to one hundred, broad. Irregular meshes sixty to eighty; three to five times as broad as the bars. By-spines zigzag, ramified, half as long as the radius.

Dimensions.--Diameter of the shell 0.15, of the meshes 0.007 to 0.014, breadth of the bars 0.003.

Habitat.--Central Pacific, Station 272, surface.

{813}B. Tribe II. #Ceriaspida#, Haeckel.

Definition.--#Dorataspida#, the spherical shell of which is composed of twenty perforated plates, produced by union of the branches of the two opposite apophyses, which arise from each radial spine. Therefore the meshes of the shell are partly sutural, partly parmal.

Genus 351. Dorataspis,[391] Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 811.

Definition.--#Dorataspida# with twenty plates, which are perforated by forty aspinal pores (two pores in each plate). Surface of the shell without combs, dimples, and by-spines.

The genus Dorataspis opens the long series of the Ceriaspida, or of those Dorataspida in which the shell is composed of twenty plates, each of which is perforated by two primary aspinal pores. This tribe has arisen from the simpler Phractaspida by reunion of the branches of the apophyses in each single spine. If in Phractaspis, their common ancestral form (Pl. 137, figs. 1, 2), the neighbouring fork-branches of both opposite apophyses in each radial spine become recurved and united, they will produce a shield, which is perforated by two pores and between them by the spine itself. These two "primary aspinal pores" are characteristic of all Ceriaspida; among these Dorataspis itself is the most simple form. Its shell exhibits therefore constantly forty aspinal pores, and besides these a variable number of "sutural pores" (in the sutures between the twenty plates). If in each suture there be only a single pore, we get on the whole fifty-two or fifty-four pores; if in each suture there be two or three pores, that number becomes doubled or tripled.

Subgenus 1. Doratasparium, Haeckel.

Definition.--Shell with fifty-two sutures; four polar plates on each pole of the main axis meeting in one point (in the pole itself); therefore all eight polar plates pentagonal and of equal size. Spherical shell therefore composed of four (equatorial) hexagonal plates and of sixteen pentagonal (eight tropical and eight polar plates).

1. Dorataspis fusigera, n. sp. (Pl. 138, fig. 2).

Shell with fifty-two sutures and fifty-two sutural meshes, with four hexagonal and sixteen pentagonal plates. Both aspinal meshes of each plate elliptical, twice to four times as broad as the {814}sutural meshes. Radial spines in the outer half fusiform, somewhat longer than the inner cylindrical half.

Dimensions.--Diameter of the shell 0.08 to 0.09, of the parmal meshes 0.1 to 0.2, of the sutural meshes 0.004 to 0.01.

Habitat.--Central Pacific, Station 271, surface.

2. Dorataspis macracantha, n. sp.

Shell with fifty-two sutures and fifty-two sutural meshes; with four hexagonal and sixteen pentagonal plates. Both aspinal meshes of each plate circular, small, twice as broad as the small sutural meshes. Radial spines quadrangular, prismatic, their outer half twice to three times as long as the inner half.

Dimensions.--Diameter of the shell 0.12, of the parmal pores 0.008, of the sutural meshes 0.004.

Habitat.--South Pacific, Station 288, surface.

3. Dorataspis macropora, n. sp.

Shell with fifty-two sutures and one hundred to one hundred and fifty sutural meshes, with four hexagonal and sixteen pentagonal plates. Both aspinal meshes nearly circular, very large, five to ten times as broad as the small circular sutural meshes; the number of the latter is in this species multiplied, in each suture being two to three (commonly three) small pores. Radial spines in the outer half leaf-shaped, compressed, nearly lanceolate, longer than in the inner cylindrical half.

Dimensions.--Diameter of the shell 0.16, of the parmal pores 0.03 to 0.04, of the sutural pores 0.004 to 0.006.

Habitat.--Indian Ocean (Madagascar), Rabbe, surface.

Subgenus 2. Dorataspidium, Haeckel.

Definition.--Shell with fifty-four sutures; four polar plates on each pole of the main axis different in pairs; two major hexagonal meeting in a polar suture (the "hydrotomical suture"); two minor pentagonal, not meeting together (separated by that hydrotomical suture). Spherical shell therefore composed of eight hexagonal plates (four equatorial and four polar) and by twelve pentagonal plates (eight tropical and four polar plates).

4. Dorataspis loricata, Haeckel.

Dorataspis loricata, Haeckel, 1862, Monogr. d. Radiol., p. 415, Taf. xxi. figs. 3-6.

Shell with fifty-four sutures and fifty-four sutural meshes, with eight hexagonal and twelve pentagonal plates. Both aspinal meshes of each plate kidney-shaped or roundish, nearly of the {815}same size as the sutural meshes. Radial spines cylindrical; their outer half on the pointed distal end two-edged and longer than the inner half.

Dimensions.--Diameter of the shell 0.14, of its meshes 0.008 to 0.016.

Habitat.--Mediterranean (Messina), North Atlantic (Canary Islands), Azores, surface.

5. Dorataspis typica, n. sp. (Pl. 138, figs. 4, 4_a_).

Shell with fifty-four crest-like sutures and fifty-four circular sutural meshes, with eight hexagonal and twelve pentagonal plates. Both aspinal meshes of each plate elliptical, twice to three times as broad as the sutural meshes. Aspinal meshes of the four equatorial plates twice as broad as those of the sixteen other plates. The meshes are surrounded by elevated and denticulated crests (incipient spine-sheaths). Radial spines compressed, more or less two-edged; outer pointed half somewhat larger than the inner half. (In this typical species the composition of the shell prevailing in the majority of Ceriaspida is very clear.)

Dimensions.--Diameter of the shell 0.15 to 0.18, of the aspinal pores 0.02 to 0.03, of the sutural pores 0.01.

Habitat.--Central Pacific, Stations 270 to 274, surface and in various depths.

6. Dorataspis micropora, n. sp. (Pl. 138, fig. 3).

Shell with fifty-four sutures and fifty-four very small sutural meshes, with eight hexagonal and twelve pentagonal plates. Both aspinal meshes of each plate elliptical, four to six times as broad as the sutural meshes. Radial spines in the outer half conical, somewhat shorter than in the inner cylindrical half.

Dimensions.--Diameter of the shell 0.11, of the aspinal pores 0.01 to 0.02, of the sutural pores 0.003.

Habitat.--North Pacific, Station 244, depth 2900 fathoms.

7. Dorataspis gladiata, n. sp.

Shell with fifty-four sutures and one hundred to one hundred and twenty sutural meshes, with eight hexagonal and twelve pentagonal plates. Both aspinal meshes elliptical, three times as broad as the small sutural meshes; commonly two meshes in each suture. Radial spines sword-shaped, two-edged, tapering from the shell towards the two ends. (Resembles Belonaspis datura, Pl. 139, fig. 9, but differs in the spherical shell, the equal size of the four equatorial spines, and the absence of by-spines.)

Dimensions.--Diameter of the shell 0.12, of the aspinal pores 0.012, of the sutural pores 0.004.

Habitat.--Indian Ocean (Madagascar), Rabbe, surface.

8. Dorataspis polypora, n. sp.

Shell with fifty-four sutures and one hundred and sixty to two hundred sutural meshes, with eight hexagonal and twelve pentagonal plates. Commonly three meshes (sometimes four) on {816}each suture. Both aspinal meshes kidney-shaped, four times as broad as the small sutural meshes. Radial spines thick, in the inner longer part cylindrical, in the outer shorter part conical. (Differs from all other species in the multiplication of the sutural pores.)

Dimensions.--Diameter of the shell 0.2, of the aspinal pores 0.016, of the sutural pores 0.004.

Habitat.--Equatorial Atlantic, Station 347, surface.

Genus 352. Diporaspis,[392] n. gen.

Definition.--#Dorataspida# with twenty plates, which are perforated by forty aspinal pores (two pores in each plate). Surface of the shell without combs and dimples, but armed with numerous by-spines.

The genus Diporaspis has the same characteristic structure of the shell as the typical Dorataspis, and differs from it only in the development of numerous by-spines on the surface. The number of the sutures between the twenty plates is sometimes fifty-two, at other times fifty-four, and in each suture we find occasionally a single pore, at other times two or three such pores.

Subgenus 1. Diporasparium.

Definition.--Shell with fifty-two sutures, four polar plates on each pole of the main axis meeting in one common point; therefore all eight polar plates pentagonal and of equal size. Shell therefore composed of four (equatorial) hexagonal plates, and of sixteen pentagonal (eight tropical and eight polar) plates.

1. Diporaspis nephropora, n. sp. (Pl. 134, fig. 15).

Shell with fifty-two sutures and fifty-two sutural pores, with four hexagonal and sixteen pentagonal plates. Both aspinal pores of each plate kidney-shaped, about twice as broad as the circular sutural pores. Radial spines thin, cylindrical, longer than the radius. By-spines forked, only one-third as long as the radius.

Dimensions.--Diameter of the shell 0.13, parmal pores 0.03, sutural pores 0.07.

Habitat.--North Pacific, Station 244, surface.

2. Diporaspis circopora, n. sp.

Shell with fifty-two sutures and one hundred to one hundred and fifty sutural pores, with four hexagonal and sixteen pentagonal plates. Both aspinal pores of each plate circular, very large, six to eight times as broad as the small circular sutural pores (in each suture two to three pores). {817}Radial spines strongly compressed, two-edged; outer half shorter than the inner. By-spines undulate, half as long as the radius.

Dimensions.--Diameter of the shell 0.12, of the parmal pores 0.02 to 0.03, of the sutural pores 0.003 to 0.004.

Habitat.--South Pacific, Station 287, surface.

Subgenus 2. Diporaspidium, Haeckel.

Definition.--Shell with fifty-four sutures, four polar plates on each pole of the main axis different in pairs: two major hexagonal meeting in a polar ("geotomical") suture, two minor pentagonal, not meeting together (separated by that suture). Shell therefore composed of eight hexagonal plates (four equatorial and four polar) and of twelve hexagonal plates (eight tropical and four polar).

3. Diporaspis zygopora, n. sp.

Shell with fifty-four sutures and fifty-four circular sutural pores: with eight hexagonal and twelve pentagonal plates. Both aspinal pores of each plate elliptical, three times as broad as the sutural pores. Radial spines compressed, two-edged; outer half shorter than the inner. By-spines very numerous, simple, one-third as long as the radius, forming coronels or elegant circles around the pores (a small coronel around each sutural pore, a large one around each couple of aspinal pores).

This typical species is nearly allied to Dorataspis typica (Pl. 138, fig. 4), and may be derived from it by development of the coronels of by-spines.

Dimensions.--Diameter of the shell 0.16, aspinal pores 0.03, sutural pores 0.01.

Habitat.--Central Pacific, Station 271, surface

Genus 353. Orophaspis,[393] Haeckel, 1881, Prodromus, p. 468.

Definition.--#Dorataspida# with twenty plates, which are perforated by forty aspinal pores (two pores in each plate). Surface of the shell without combs, dimples, and by-spines. Each radial spine bears outside of the shell two opposite free apophyses, which are either simple or branched.

The genus Orophaspis differs not only from its ancestral form, Dorataspis, but from all other Dorataspida in the development of peculiar free apophyses on the radial spines, outside the shell. These apophyses, two being opposite on each spine, appear as a repetition of the primary apophyses of Phractaspis; they are either simple or branched, and sometimes the branches are united together, forming an outer free shield with two or four pores. These outer plates represent the beginning of a second outer shell and form the transition to Phractopelta, the ancestral form of the Phractopeltida.

{818}Subgenus 1. Orophasparium, Haeckel.

Definition.--Free apophyses of the radial spines simple, not branched.

1. Orophaspis astrolonche, n. sp.

Parmal pores of the shell circular, twice as large as the sutural pores and as the breadth of the bars. Radial spines very long, three to six times as long as the diameter of the shell, compressed, two-edged; each with two simple, opposite, triangular apophyses; their distance from the shell equal to its diameter.

Dimensions.--Diameter of the shell 0.05, parmal pores 0.004, sutural pores 0.002.

Habitat.--North Pacific, Station 239, surface.

2. Orophaspis gladiata, n. sp.

Parmal pores of the shell circular, of the same size as the sutural pores and the bars. Radial spines thick, spindle-shaped, scarcely longer than the diameter of the shell, each with two simple opposite conical apophyses; their distance from the shell about equal to its radius.

Dimensions.--Diameter of the shell 0.06, pores 0.003.

Habitat.--Central Pacific, Station 265, surface.

Subgenus 2. Orophaspidium, Haeckel.

Definition.--Free apophyses of the radial spines branched, their branches free (not anastomosing).

3. Orophaspis furcata, n. sp. (Pl. 133, fig. 6).

Parmal pores of the shell roundish or elliptical, three times as broad as the sutural pores and the bars. Radial spines very long, compressed, each with two opposite apophyses, which are simply forked; their distance from the shell somewhat greater than its diameter.

Dimensions.--Diameter of the shell 0.06 to 0.08, parmal pores 0.006, sutural pores 0.002.

Habitat.--Central Pacific, Station 274, surface.

4. Orophaspis ramosa, n. sp.

Parmal pores of the shell circular, of the same size as the sutural pores and the bars. Radial spines compressed, very long, each with two opposite apophyses, which are more or less irregularly branched (commonly between eight and twelve thin branches on each spine); their distance from the shell smaller than its diameter.

Dimensions.--Diameter of the shell 0.08, pores 0.006.

Habitat.--North-West Pacific, Station 235, surface.

{819}Subgenus 3. Stegaspis, Haeckel, 1881, Prodromus, p. 468.

Definition.--Free apophyses of the radial spines branched, and by reunion of their anastomosing branches forming perforated shields.

5. Orophaspis diporaspis, n. sp.

Parmal pores of the shell circular, of the same size as the sutural pores and the bars. Radial spines sword-shaped, two-edged, very broad; each spine bears an elliptical free shield with two longish pores (opposite on the two flat sides of the sword). Distance of the twenty free two-pored shields from the shell about equal to its diameter.

Dimensions.--Diameter of the shell 0.04, of the pores 0.004.

Habitat.--South Pacific, Station 295, surface.

6. Orophaspis tessaraspis, n. sp.

Parmal pores of the shell roundish, somewhat larger than the sutural pores and the bars. Radial spines very long, compressed; each spine bears a roundish free shield with four irregular pores disposed in a cruciform manner, the two larger pores being opposite on the flat sides of the spine, the two smaller being opposite but on its two edges. Distance of the twenty free four-pored shields from the shell about equal to its radius.

Dimensions.--Diameter of the shell 0.05, of the pores 0.003.

Habitat.--North Pacific, Station 239, surface.

Genus 354. Ceriaspis,[394] Haeckel, 1881, Prodromus, p. 468.

Definition.--#Dorataspida# with twenty plates, which are perforated by forty aspinal pores (two pores in each plate). Surface of the shell with numerous dimples, separated by a network of elevated combs. No by-spines.

The genus Ceriaspis has the same structure of the shell, as its ancestral form Dorataspis, differing from it only in the development of high combs or crests, which form on the surface of the shell a peculiar elevated network. The dimples or funnel-shaped pits between these combs are either all or partly perforated by the pores of the shell. Both the aspinal pores of each plate are usually placed in one common dimple, whilst each sutural pore is placed in its peculiar smaller dimple.

Subgenus 1. Ceriasparium, Haeckel.

Definition.--Shell-surface with seventy to one hundred or more small funnel-shaped dimples, each of which opens on the bottom by one pore or by a couple of {820}apertures; twenty larger dimples in the centre of the plates (each with a couple of aspinal pores) and fifty to one hundred or more smaller dimples, each of which contains one sutural pore. No blind dimples between the perforated dimples.

1. Ceriaspis lacunosa, n. sp.

Shell spherical with seventy-two funnel-shaped dimples, each of which is perforated on the bottom by one or two apertures; twenty larger dimples in the centre of the plates, each with two elliptical aspinal pores, and fifty-two smaller sutural dimples between them, each with one circular pore of half the size. No blind dimples. Radial spines quadrangular, stout; their outer part shorter than the inner.

Dimensions.--Diameter of the shell 0.1, of the forty parmal pores 0.01, of the fifty-two sutural pores 0.005.

Habitat.--South Atlantic, Station 330, surface.

2. Ceriaspis scrobiculata, n. sp.

Shell spherical, with seventy-four funnel-shaped dimples, each of which is perforated on the bottom by one or two apertures; twenty larger dimples in the centre of the plates, each with two kidney-shaped large pores, and fifty-four smaller dimples on the sutures, each with one circular pore of one-fourth of the size of the reniform pores. No blind dimples. Radial spines cylindrical, the outer part longer than the inner.

Dimensions.--Diameter of the shell 0.12, of the forty parmal pores 0.016, of the fifty-four sutural pores 0.004.

Habitat.--Central Pacific, Station 270, surface.

Subgenus 2. Ceriaspidium, Haeckel.

Definition.--Shell-surface with funnel-shaped dimples (commonly one hundred and seventy-six or one hundred and eighty-two), which on the bottom are partly closed, partly perforated by one aperture (or by a pair of pores). The blind dimples are placed on the corners of the twenty plates, and are therefore either one hundred and four or one hundred and eight; if there be no polar suture, the blind dimples are one hundred and four (twenty-four on the four hexagonal equatorial plates, forty on the eight pentagonal tropical plates, and forty on the eight pentagonal polar plates); if, however, there be a polar suture on both main poles, the number of blind dimples is one hundred and eight (twenty-four on the four hexagonal equatorial and twenty-four on the four hexagonal polar plates, two opposite on each pole; forty on the eight pentagonal tropical plates and twenty on the four pentagonal polar plates, two opposite on each pole). Between the blind dimples there are usually seventy-two to seventy-four perforated {821}dimples, twenty larger parmal dimples (enclosing a radial spine and a couple of aspinal pores) and fifty-two to fifty-four sutural dimples (sometimes one hundred or more), each of which encloses one sutural pore.

3. Ceriaspis inermis, n. sp. (Pl. 138, fig. 5).

Shell spherical, with one hundred and seventy-six funnel-shaped dimples, one hundred and four of which are blind and seventy-two perforated; of the latter, each of the fifty-two smaller contains a single sutural pore, each of the twenty larger a couple of aspinal pores. The elliptical or kidney-shaped aspinal pores are about twice as broad as the circular sutural pores. Radial spines thin, compressed, two-edged; their outer prolongation very short, rudimentary, scarcely higher than the axis of the surrounding funnel, and projecting but slightly from its aperture.

Dimensions.--Diameter of the shell 0.15, of the forty parmal pores 0.016, of the fifty-two sutural pores 0.008.

Habitat.--South Pacific, Station 289, surface.

4. Ceriaspis favosa, n. sp. (Pl. 138, fig. 6).

Shell polyhedral (icosahedral), with one hundred and eighty-two funnel-shaped dimples, one hundred and eight of which are blind and seventy-four perforated; of the latter, each of the fifty-four smaller contains a single sutural pore, each of the twenty larger a couple of aspinal pores. All pores roundish, nearly of the same size. Radial spines thin, compressed, two-edged; their outer part somewhat longer than the inner.

Dimensions.--Diameter of the shell 0.12 to 0.13, of the pores 0.01 to 0.015.

Habitat.--Central Pacific, Station 274, surface.

5. Ceriaspis icosahedra, n. sp.

Shell polyhedral (icosahedral), with one hundred and eighty-two funnel-shaped dimples, one hundred and eight of which are blind and seventy-four perforated; of the latter, each of the fifty-four smaller contains one small sutural pore, each of the twenty larger a couple of aspinal pores. The kidney-shaped aspinal pores are very large, four to six times as broad as the small circular sutural pores. Radial spines strong, quadrangular, their outer part from two to three times as long as the inner part.

Dimensions.--Diameter of the shell 0.16, of the parmal pores 0.015 to 0.02, of the sutural pores 0.003 to 0.004.

Habitat.--Tropical Atlantic, Station 349, surface.

6. Ceriaspis cicatricosa, n. sp.

Shell spherical, with two hundred and fifty to three hundred (or more) small funnel-shaped dimples, the majority of which are blind, the minority perforated by pores; of the latter forty {822}are aspinal pores (two at the base of each spine), the others sutural pores. All pores nearly of the same size. As the shell of this species is very dark and thick-walled, it was impossible to obtain more information with regard to the pores. Radial spines very stout; the outer conical part shorter than the inner cylindrical part.

Dimensions.--Diameter of the shell 0.2, of the pores 0.006 to 0.008.

Habitat.--North Pacific, Station 236, surface.

Genus 355. Hystrichaspis,[395] n. gen.

Definition.--#Dorataspida# with twenty plates, which are perforated by forty aspinal pores (two pores in each plate). Surface of the shell with numerous dimples, separated by a network of elevated combs. Numerous by-spines.

The genus Hystrichaspis has the same structure with regard to the shell, as its ancestral form Ceriaspis, and differs from the latter only in possessing numerous by-spines. Moreover, in the former the dimples of the shell-surface are either all perforated by pores, or some of them are blind.

Subgenus 1. Hystrichasparium, Haeckel.

Definition.--Shell with seventy to one hundred or more funnel-shaped dimples, each of which opens on the bottom by one aperture or by a couple of pores; twenty larger dimples in the centre of the plates (each with a couple of pores, sometimes also three couples) and fifty to one hundred or more smaller dimples, each of which contains one sutural pore. No blind dimples between the perforated dimples.

1. Hystrichaspis pectinata, n. sp. (Pl. 138, fig. 8).

Shell with numerous (one hundred to two hundred?) funnel-shaped dimples, each of which is pierced at the bottom by one or two pores; twenty larger dimples in the centre of the plates (each with two aspinal pores), and fifty to one hundred and fifty or more smaller dimples (each with one sutural pore). No blind dimples. Crests between the dimples armed with a continuous series of simple by-spines. Radial main spines stout, in the inner half cylindrical, in the outer conical, more or less compressed.

Dimensions.--Diameter of the shell 0.13, of the pores 0.004 to 0.006.

Habitat.--Tropical Atlantic, Station 352, surface.

2. Hystrichaspis furcata, n. sp. (Pl. 138, fig. 9).

Shell with numerous (one hundred to two hundred?) funnel-shaped dimples, each of which is pierced at the bottom by one or two pores; twenty larger dimples in the centre of the plates (each {823}with two large aspinal pores), and fifty to one hundred and fifty or more smaller dimples (each with one small sutural pore). No blind dimples. Crests between the dimples armed with forked by-spines. Radial main spines stout, leaf-shaped, tapering towards both ends.

Dimensions.--Diameter of the shell 0.12, parmal pores 0.01, sutural pores 0.005.

Habitat.--Central Pacific, Station 276, surface.

3. Hystrichaspis cristata, n. sp. (Pl. 138, fig. 11).

Siphonasphis cristata, Haeckel, 1882, Manuscript.

Shell with numerous (one hundred to two hundred?) funnel-shaped dimples, each of which is pierced at the bottom by one or more pores. Twenty larger dimples in the centre of the plates are pierced by the radial main-spines; among these fourteen contain each a couple of aspinal pores; six others are much larger, and contain each six larger pores; these six plates are two opposite equatorial plates and four polar plates, placed in the same meridian plane (the "hydrotomical plane"); in each of these six "hydrotomical dimples" two pores are placed opposite to one another on the two edges of the leaf-shaped spine, four others being opposite in pairs on both flat sides of it. By this peculiar structure this species connects the true Hystrichaspis with Hexalaspis and Diploconus; however the twenty spines are of equal length, and the shell continues to be spherical. The twenty radial main-spines are leaf-like and compressed. The crests between the dimples are dentated by a series of small by-spines.

Dimensions.--Diameter of the shell 0.15, of the aspinal pores 0.01, of the sutural pores 0.005.

Habitat.--North Pacific, Station 240, surface.

Subgenus 2. Hystrichaspidium, Haeckel.

Definition.--Shell-surface with numerous funnel-shaped dimples (commonly one hundred and seventy-six to one hundred and eighty-two), which on the bottom are partly closed, partly perforated by one aperture (or by a pair of pores). The blind dimples are situated on the corners of the twenty plates; their number is commonly one hundred and four or one hundred and eight, sometimes more. The perforated dimples, alternating with the former, are usually seventy-two to seventy-four, sometimes more; twenty larger parmal dimples (each with a couple of aspinal pores, sometimes also with three such couples) and fifty-two to fifty-four sutural dimples, sometimes one hundred or more (each with one sutural pore). (Compare the definition of Ceriaspidium, p. 820.)

4. Hystrichaspis dorsata, n. sp. (Pl. 138, fig. 10).

Shell with one hundred and seventy-six funnel-shaped dimples, one hundred and four of which are blind and seventy-two perforated; of the latter, each of the fifty-two smaller contains a single {824}sutural pore, each of the twenty larger a couple of aspinal pores; the elliptical aspinal pores are twice as broad as the circular sutural pores. The crests between the dimples are armed with simple scattered short by-spines; usually in the nodal points, where three combs meet, there exist three or two divergent by-spines. The twenty radial main-spines are thin and long, compressed.

Dimensions.--Diameter of the shell 0.22, of the aspinal pores 0.02, of the sutural pores 0.01.

Habitat.--Central Pacific, Station 271, surface.

5. Hystrichaspis armata, n. sp.

Shell with one hundred and seventy-six funnel-shaped dimples, one hundred and four of which are blind and seventy-two perforated; of the latter, each of the fifty-two smaller contains a single sutural pore, each of the twenty larger a couple of aspinal pores. Crests between the dimples comb-like, armed with a series of simple by-spines. Twenty main-spines very stout, in the inner part cylindrical, in the outer shorter part conical.

Dimensions.--Diameter of the shell 0.25, of the aspinal pores 0.02, of the sutural pores 0.01.

Habitat.--South-East Pacific, Station 300, surface.

6. Hystrichaspis sulcata, n. sp.

Shell with one hundred and eighty-two funnel-shaped dimples, one hundred and eight of which are blind and seventy-four perforated; of the latter, each of the fifty-four smaller contains a single sutural pore, each of the twenty larger a couple of aspinal pores. All pores nearly of the same size, very small. Crests between the dimples very high, sulcated, on the free edge serrate with short very numerous, simple by-spines. Radial main-spines very stout and short, conical.

Dimensions.--Diameter of the shell 0.2, of the pores 0.003.

Habitat.--South Atlantic, Station 325, surface.

7. Hystrichaspis foveolata, n. sp.

Shell with very numerous (three hundred to four hundred?) small and deep funnel-shaped dimples, the majority of which are blind, the minority perforated; among the latter there are forty larger aspinal pores; the other smaller (scarcely half as large) pores are sutural. Crests between the dimples densely armed with simple short by-spines. Radial main-spines stout, leaf-shaped.

Dimensions.--Diameter of the shell 0.12, of the aspinal pores 0.01, of the sutural pores 0.004.

Habitat.--Tropical Atlantic, Station 338, surface.

8. Hystrichaspis divaricata, n. sp.

Shell with numerous (two hundred to three hundred?) funnel-shaped dimples, the majority of which are blind, the minority perforated; among the latter there are forty larger aspinal pores. {825}Crests between the dimples armed with long forked by-spines with divergent fork-branches. Radial spines cylindrical, very long and thick, longer than the diameter of the shell.

Dimensions.--Diameter of the shell 0.14, aspinal pores 0.08, sutural pores 0.03.

Habitat.--Central Pacific, Station 266, surface.

9. Hystrichaspis fruticata, n. sp. (Pl. 138, fig, 7).

Shell with numerous (one hundred and fifty to two hundred?) funnel-shaped dimples, the majority of which are blind, the minority perforated; forty aspinal pores elliptical, of the same size as the circular sutural pores. Crests between the dimples bearing elegant arborescent by-spines. Twenty radial main-spines long and thin, cylindrical or a little compressed.

Dimensions.--Diameter of the shell 0.17, pores 0.01.

Habitat.--Tropical Pacific, Station 275, surface.

10. Hystrichaspis serrata, n. sp.

Shell with numerous (two hundred to three hundred?) funnel-shaped dimples, the majority of which are blind, the minority perforated; forty aspinal pores of the same size as the sutural pores. Crests between the dimples covered with denticulated by-spines. Twenty radial main-spines compressed, two-edged, with serrated edges, about as long as the diameter of the shell.

Dimensions.--Diameter of the shell 0.21, pores 0.012.

Habitat.--North Pacific, Station 238, surface.

Genus 356. Coscinaspis,[396] n. gen.

Definition.--#Doratispida# with twenty plates, which are perforated by eighty to two hundred or more parmal pores (two aspinal and two to ten or more coronal pores in each plate). Surface without by-spines.

The genus Coscinaspis, together with the following nearly allied genus Acontaspis, may be separated from the other Ceriaspida as a peculiar tribe, Coscinaspida. This tribe is characterised by the larger number of the parmal pores. Whilst in all other Ceriaspida this number is constantly forty (only two pores in each plate), here it may be from eighty to two hundred or more; in each shield the two primary "aspinal pores" are surrounded by a circle of two to ten or more (commonly eight to twelve) "coronal pores." The number of sutural pores in this group is also usually larger.

{826}Subgenus 1. Coscinasparium, Haeckel.

Definition.--Plates of the shell smooth, without crests, not dimply.

1. Coscinaspis peripora, n. sp. (Pl. 138, fig. 1).

Shell thin walled, with smooth surface, without crests and dimples, perforated by pores of very different sizes. Forty aspinal pores, roundish or elliptical, of about the same size as the fifty or sixty violin-shaped sutural pores, and three to four times as broad as the small roundish coronal pores, which are irregularly formed and distributed, four to eight occurring on each plate (altogether one hundred to one hundred and twenty). Radial spines roundish, somewhat compressed; inner and outer half nearly of the same length.

Dimensions.--Diameter of the shell 0.12, aspinal pores 0.01 to 0.012, coronal pores 0.003.

Habitat.--North-West Pacific, Station 235, surface.

2. Coscinaspis stigmopora, n. sp.

Shell very thin walled, with smooth surface, without crests and dimples, perforated by pores of very different sizes. Forty aspinal pores, roundish, of about the same size as the fifty or sixty violin-shaped sutural pores, their diameter being about one-fifth of that of the plates. Coronal pores very numerous (two hundred to four hundred) and very small, irregularly scattered, ten to twenty occurring in each plate. Sutures strongly denticulated. Radial spines very thin and short, cylindrical.

Dimensions.--Diameter of the shell 0.12 to 0.15, aspinal and sutural pores 0.01, coronal pores 0.001 to 0.003.

Habitat.--North Pacific, Station 257, surface.

3. Coscinaspis rhacopora, n. sp.

Shell very thin walled, with smooth surface, without crests and dimples, perforated by very irregular pores of very different sizes and forms; commonly more or less lobed or sinuate. Forty aspinal pores and fifty to eighty sutural pores, larger than the numerous (one hundred to two hundred) irregularly scattered coronal pores. Sutures very sinuate. Radial spines cylindrical, thin and long.

Dimensions.--Diameter of the shell 0.15 to 0.18, aspinal and sutural pores 0.01 to 0.02, coronal pores 0.001 to 0.005.

Habitat.--Central Pacific, Station 274.

4. Coscinaspis coscinopora, n. sp.

Shell thin walled, with smooth surface, without crests and dimples, perforated by very numerous pores of circular form, but of different sizes. Forty aspinal pores and one hundred to two hundred {827}sutural pores much larger than the coronal pores, which are very small and very numerous (fifty to sixty on each plate). Sutures sinuate. Radial spines compressed, outer and inner half nearly of equal length.

Dimensions.--Diameter of the shell 0.3, aspinal and sutural pores 0.01 to 0.015, coronal pores 0.001 to 0.002.

Habitat.--Tropical Atlantic, Station 338, surface.

5. Coscinaspsis polypora, n. sp. (Pl. 136, fig. 8).

Shell very thin walled, with smooth surface, without crests and dimples, the two aspinal pores of each plate narrow, lanceolate, ten to twelve times as long as broad and half as long as the radius of each plate. Coronal pores irregular, polygonal, very numerous (two hundred to three hundred on each plate), commonly arranged more or less regularly in ten to twelve series parallel to the longitudinal diameter of the aspinal spines (ten to twenty pores in each series). Sutural pores irregular, polygonal, very numerous. Radial spines very thin and long, cylindrical.

Dimensions.--Diameter of the shell 0.24; length of the aspinal pores 0.04, breadth 0.004; coronal and sutural pores 0.002 to 0.01.

Habitat.--Tropical Atlantic, Station 349, surface.

6. Coscinaspis orthopora, n. sp.

Shell very thin walled, with smooth surface, without crest and dimples. All pores of nearly equal size and form; quadrangular, mostly rectangular; one hundred to two hundred, separated by two systems of parallel bars, perpendicular one to another, occur in each plate. Sutural pores mostly triangular. Radial spines very thin and long, cylindrical, somewhat compressed. (Similar to those of Phatnaspis lacunaria, Pl. 136, fig. 9, but spherical, not ellipsoidal.)

Dimensions.--Diameter of the shell 0.2, pores 0.008 to 0.012.

Habitat.--Central Pacific, Station 272, surface.

7. Coscinaspis parmipora, n. sp. (Pl. 137, fig. 9).

Craniaspis parmipora, Haeckel, 1866, Manuscript.

Dorataspis parmipora, Haeckel, 1881, Prodromus, Atlas.

Shell thin walled, with smooth surface, without crests and dimples. There are no sutural pores, since all twenty plates are connected by perfect sinuate sutures (therefore this excellent species may perhaps better represent a peculiar genus, called by me in 1866 Craniaspis). All pores are parmal pores; each plate with two elliptical aspinal pores, which are twice to five times broader than the numerous, roundish irregularly scattered coronal pores (thirty to fifty occurring on each plate). The radial spines are quite internal, that is, not prolonged on the outside of the shell; in this respect they resemble those of Sphærocapsa.

Dimensions.--Diameter of the shell 0.16, aspinal pores 0.01, coronal pores 0.002 to 0.005.

Habitat.--North Atlantic, Canary Islands (Lanzerote), surface.

{828}8. Coscinaspis isopora, n. sp. (Pl. 134, figs. 13, 14).

Shell thick walled, with smooth surface, without crests and dimples. All pores of the shell nearly of the same size and of similar form, about as broad as the bars between them, and about two hundred in number, viz., fifty to sixty (regularly fifty-two or fifty-four) sutural pores and one hundred and forty to one hundred and fifty parmal pores (forty aspinal kidney-shaped pores, and one hundred to one hundred and ten coronal circular pores: six in the angles of each equatorial plate, and five in the angles of each tropical and polar plate; if the disposition be quite regular, one hundred and four or one hundred and eight). Radial spines short, rudimentary, conical.

Dimensions.--Diameter of the shell 0.2, of the pores and bars 0.012.

Habitat.--Tropical Pacific, Station 218 (off New Guinea), surface.

Subgenus 2. Coscinaspidium, Haeckel.

Definition.--Surface of the shell dimply, with a network of prominent crests.

9. Coscinaspis ceriopora, n. sp.

Shell thick-walled, with numerous (one hundred and sixty to two hundred?) funnel-shaped dimples, which are separated by prominent crests; on the bottom of each dimple there is a simple or double circular pore. If this species be quite regularly developed, it closely resembles the preceding, differing from it mainly in the prominent combs of the surface. It resembles also Ceriaspis favosa, Pl. 138, fig. 6; but whilst in this latter the majority of the dimples are blind, here they are all perforated. The twenty aspinal dimples (in the centre of each plate) present at the bottom a couple of pores, all other dimples a single pore. Among the latter there are fifty to sixty sutural pores and one hundred to one hundred and ten coronal pores, viz., six in each equatorial plate, and five in each of the other plates; but the number is not quite constant. Radial spines strong, in the inner part cylindrical, in the outer conical.

Dimensions.--Diameter of the shell 0.15, of the pores and bars 0.01.

Habitat.--Tropical Pacific, Station 215, surface.

Genus 357. Acontaspis,[397] Haeckel, 1881, Prodromus, p. 468.

Definition.--#Dorataspida# with twenty plates, which are perforated by eighty to two hundred or more parmal pores (in each plate two aspinal and two to ten or more coronal pores). Surface covered with by-spines.

The genus Acontaspis has the same characteristic structure of the shell as Ceriaspis, differing from it only in the presence of numerous by-spines. Each plate is perforated by four to sixteen or more (commonly ten to twelve) parmal pores, the two central of which are primary "aspinal pores," all the others being secondary "coronal pores."

{829}Subgenus 1. Acontasparium, Haeckel.

Definition.--Plates of the shell not dimply, without prominent crests.

1. Acontaspis lanceolata, n. sp.

Shell thin walled, even, without crests and dimples between them, perforated by about three hundred pores of different sizes: forty aspinal pores elliptical, about as large as the irregular (fifty to sixty) sutural pores, and two to four times as broad as the small circular coronal pores (eight to twelve being on each plate, altogether about two hundred). Between the pores numerous short conical by-spines. Radial main spines lanceolate, about as long as the radius. (Similar to Coscinaspis peripora, Pl. 138, fig. 1, but with broad lanceolate spines and numerous short by-spines.)

Dimensions.--Diameter of the shell 0.15, aspinal and sutural pores 0.012 to 0.015, coronal pores 0.004 to 0.008.

Habitat.--South Atlantic, Station 325, surface.

Subgenus 2. Acontaspidium, Haeckel.

Definition.--Surface of the shell dimply, with a network of prominent crests.

2. Acontaspis hastata, n. sp. (Pl. 134, fig. 16).

Shell thick walled, with numerous (one hundred and seventy to one hundred and ninety) dimples, which are separated by an elevated network of prominent crests. In the centre of each plate a larger dimple with a couple of aspinal pores, surrounded by a corona of ten or twelve smaller dimples, each of which contains a single pore (a coronal and sutural alternately). All pores circular or roundish, nearly of the same size. If the shell be quite regularly developed, there are fifty to sixty sutural pores and one hundred to one hundred and ten coronal pores (six in each equatorial plate, five in each of the other plates). The knobs of the meeting crests are conical, and bear each a simple short by-spine. Radial main spines compressed, at the distal end spear-shaped, with a rhomboidal plate below the apex, about as long as the radius.

Dimensions.--Diameter of the shell 0.18, of the pores and bars 0.01.

Habitat.--Western Tropical Pacific (off the Philippines), Station 215.

3. Acontaspis furcata, n. sp.

Shell thick walled, dimply, with a network of crests, of the same composition as in the foregoing species, with one hundred and seventy to one hundred and ninety dimples (twenty aspinal, one hundred to one hundred and ten coronal and fifty to sixty sutural dimples). All dimples and pores nearly of the same size. Each node of the crested network bears a stout by-spine, which is forked {830}on the base, with two divergent straight branches (similar to those of Hystrichaspis furcata, Pl. 138, fig. 9). Radial main spines two-edged, sword-like, nearly as long as the diameter of the shell.

Dimensions.--Diameter of the shell 0.13, of the pores 0.008.

Habitat.--Central Pacific, Station 272, surface.

4. Acontaspis capillata, n. sp.

Shell very dark and thick walled, non-transparent, with very numerous (three hundred to four hundred or more?) deep funnel-shaped dimples, each of which is perforated by a small circular pore (forty aspinal, two hundred to three hundred coronal, and fifty to one hundred sutural pores?). The high crests between the dimples bear very numerous simple by-spines, nearly half as long as the radius, so that the shell appears covered with hairs. Radial main spines very long and thin, cylindrical, longer than the diameter of the shell.

Dimensions.--Diameter of the shell 0.2, of the pores 0.012.

Habitat.--North Pacific, Station 244, surface.

Subfamily 2. TESSARASPIDA, Haeckel.

Definition.--#Dorataspida# with twenty radial spines, each of which bears four crossed apophyses (opposite in pairs). The spherical shell is composed either of the meeting branches of these apophyses (Stauraspida), or of twenty perforated plates, produced by concrescence of their branches (Lychnaspida).

A. Tribe II. #Stauraspida#, Haeckel, 1881, Prodromus, p. 467.

Definition.--#Dorataspida# with spherical shell, which is composed either of the meeting branches of the four crossed apophyses only, or exhibits four to twelve perforated plates which are produced by the crossed apophyses of four to twelve radial spines (but never of all twenty spines). Each plate bears four crossed pores.

Genus 358. Stauraspis,[398] Haeckel, 1881, Prodromus, p. 467.

Definition.--#Dorataspida# without perforated plates; shell composed only of the meeting branches of the four crossed apophyses, which arise (opposite in pairs) from each radial spine. Condyles of the branch-ends without by-spines.

The genus Stauraspis is the most simple and primitive form among all Tessaraspida, or that subfamily of Dorataspida, in which the shell is composed of twenty {831}radial spines, each of which bears four crossed apophyses. The subfamily may be divided into two different tribes, the Stauraspida and Lychnaspida. In the Stauraspida either all twenty spines, or a part of them, bear no perforated plates, and the shell is composed wholly or partially of the meeting branches of their apophyses. In the Lychnaspida, however, the four apophyses of each single spine form, by reunion of their recurved branches, a plate or shield with four crossed aspinal pores. The Lychnaspida represent therefore a more developed stage in the shell-formation than the simpler Stauraspida. Stauraspis, as the common ancestral form of both, may be derived phylogenetically from Xiphacantha or Stauracantha, which differ only by the apophyses or branches of the apophyses not meeting. These branches (originally eight on each spine) are either simple or again branched.

Subgenus 1. Staurasparium, Haeckel.

Definition.--Apophyses of the spines simple, not branched; therefore each spine with four sutural condyles.

1. Stauraspis cruciata, n. sp. (Pl. 134, fig. 5).

Radial spines thin, quadrangular, prismatic; outer and inner half nearly of equal length. Central bases pyramidal, with wing-like edges. Four apophyses of each spine simple, not branched, with thin condyles. Large meshes of the shell ten to twenty times as broad as the bars. This and the following species greatly resemble the simplest forms of Phractaspis (Pl. 137, figs. 1, 2); they differ from these, however, by the equal size and distance of the four branches of each spine, which thus form a rectangular cross.

Dimensions.--Diameter of the shell 0.1; breadth of the spines and bars 0.002.

Habitat.--Central Pacific, Station 268, surface.

2. Stauraspis xiphacantha, n. sp.

Radial spines stout, cylindrical in the inner half, conical in the shorter outer half. Four apophyses of each spine simple, not branched, broad, with thick condyles. Meshes of the shell six to eight times as broad as the bars.

Dimensions.--Diameter of the shell 0.12; breadth of the spines and bars 0.008 to 0.01.

Habitat.--South Pacific, Station 290, surface.

Subgenus 2. Stauraspidium, Haeckel.

Definition.--Apophyses of the spines branched; therefore each spine with eight to twenty or more sutural condyles.

{832}3. Stauraspis furcata, n. sp.

Radial spines thin, quadrangular, prismatic; outer and inner halves nearly of equal length. The four apophyses of each spine simply forked (or partly with bifid fork-branches); each spine with eight to twelve sutural condyles. Meshes of the shell ten to twenty times as broad as the bars.

Dimensions.--Diameter of the shell 0.15; breadth of the spines and bars 0.003.

Habitat.--Central Pacific, Station 266, surface.

4. Stauraspis stauracantha, n. sp. (Pl. 137, figs. 5, 6).

Radial spines thin, in the inner longer half cylindrical, in the outer half conical with thickened base. Four apophyses of each spine doubly forked or dichotomously (more or less irregularly) branched; each spine with sixteen to twenty-four sutural condyles. Meshes of the shell of very different sizes and forms; the largest ten to fifteen, the smallest two to three times as broad as the bars.

Dimensions.--Diameter of the shell 0.14; breadth of of the spines 0.002 to 0.01, of the bars 0.002.

Habitat.--Tropical Atlantic, Station 343, surface.

Genus 359. Echinaspis,[399] Haeckel, 1881, Prodromus, p. 467.

Definition--#Dorataspida# without perforated plates; shell composed only of the meeting branches of the four crossed apophyses, which arise (opposite in pairs) from each radial spine. Condyles of the branch-ends bearing by-spines.

The genus Echinaspis exhibits the same structure of the shell as its ancestral form Stauraspis, and differs from it only in the development of by-spines on the sutural condyli.

1. Echinaspis dichotoma, n. sp.

Radial spines cylindrical, thin, outer half longer than the inner. Four apophyses of each spine simply forked (or partly with bifid fork-branches); therefore each spine usually possesses eight (sometimes ten to twelve) sutural condyles. Meshes of the shell ten to twelve times as broad as the bars. Each condyle bears a zigzag by-spine, half as long as the radius.

Dimensions.--Diameter of the shell 0.12, of the spines 0.004 to 0.006.

Habitat.--North Pacific, Station 253, surface.

{833}2. Echinaspis diadema, n. sp.

Radial spines thin and long, quadrangular, prismatic; outer half two to three times as long as the inner. Four apophyses of each spine simply forked (or partly with bifid fork-branches); each spine with eight to twelve sutural condyles. Meshes of the shell fifteen to twenty-five times as broad as the bars. Each condyle bears a simple bristle-shaped by-spine, nearly as long as the radius.

Dimensions.--Diameter of the shell 0.11; breadth of the spines and bars 0.002.

Habitat.--South Atlantic, Station 333, surface.

3. Echinaspis echinoides, n. sp. (Pl. 137, figs. 7,8).

Radial spines roundish, in the outer half conical, and two to three times as broad as in the inner half. Four apophyses of each spine doubly forked or dichotomously (more or less irregularly) branched; each spine with sixteen to twenty-four sutural condyles. Meshes of the shell four to eight times as broad as the bars. Each condyle bears a zigzag by-spine, one-third as long as the radius.

Dimensions.--Diameter of the shell 0.15; breadth of the spines 0.004 to 0.01, of the bars 0.002.

Habitat.--Central Pacific, Station 266, surface.

Genus 360. Zonaspis,[400] n. gen.

Definition.--#Dorataspida# with four plates, each of which is perforated by four crossed aspinal pores; these four plates are formed by the united branches of the other spines (eight polar and eight tropical) form no lattice-plates by union. Each condyle bears a by-spine.

The genus Zonaspis differs from all other Dorataspida in the peculiar formation of the four equatorial spines, which form by union of the recurved branches of their apophyses four perforated plates (each with four crossed pores), whilst the branches of the sixteen other plates do not unite to form plates, but simply meet the branches of the neighboring spines.

1. Zonaspis fragilis, n. sp.

Radial spines very thin and long, cylindrical. Four meshes of each equatorial plate pentagonal, ten to twelve times as broad as the bars. By-spines zig-zag, nearly as long as the radius.

Dimensions.--Diameter of the shell 0.16, of the parmal pores 0.018.

Habitat.--South Atlantic, Station 332, surface.

{834}2. Zonaspis cingulata, n. sp. (Pl. 134, figs. 3, 4).

Radial spines cylindrical in the inner half, with thickened pyramidal bases (fig. 3), conical in the outer half; both halves of equal length. The four meshes of each equatorial plate egg-shaped, four to six times as broad as the bars. By-spines zigzag, half as long as the radius.

Dimensions.--Diameter of the shell 0.15, of the parmal meshes 0.015.

Habitat.--Tropical Pacific (east coast off Philippines), Station 275, surface.

3. Zonaspis æquatorialis, n. sp. (Pl. 135, fig. 5).

Radial spines stout, cylindrical in the shorter inner half, conical in the longer outer half. The four meshes of each equatorial plate circular, only twice as broad as the bars. By-spines zigzag, nearly as long as the radius.

Dimensions.--Diameter of the shell 0.11, of the parmal meshes 0.008.

Habitat.--Equatorial Atlantic, Station 347, surface.

Genus 361. Dodecaspis,[401] n. gen.

Definition.--#Dorataspida# with twelve plates, each of which is perforated by four crossed aspinal pores; these twelve plates are formed by the united branches of the apophyses of four equatorial and eight polar spines. The branches of the apophyses of the eight tropical spines form no lattice-plates by union. Each condyle bears a by-spine.

The genus Dodecaspis differs from all other Dorataspida in the peculiar composition of its shell; twelve spines (four equatorial and eight polar spines) form by union of the branches of their apophyses twelve plates, each of which exhibits four crossed pores, whilst the eight other (tropical) spines form no perforated plates, but simply unite with the neighbouring spines by meeting branches. Some irregularity is often to be found in this genus; instead of four pores in each plate there may be two closed, the other two which are opposite being open. Several times I observed a peculiar "hemihedral" variety: only six spines of one meridian plane (the two equatorial and the four polar spines of the "hydrotomical" plane) exhibited complete shields, whilst the branches of the other fourteen plates remained open. This "hemihedral" form may perhaps represent a peculiar genus, Hemiaspis.

1. Dodecaspis tricinata, n. sp. (Pl. 134, fig. 1).

Radial spines thin and long, cylindrical. The four meshes of each equatorial and each polar plate of equal size, pentagonal, about eight times as broad as the bars. By-spines zigzag, nearly as long as the radius. In this species the hemihedral variety, Hemiaspis, often occurs.

Dimensions.--Diameter of the shell 0.15, of the parmal pores 0.016.

Habitat.--South-east Pacific (west coast of Patagonia), Station 302, surface.

{835}2. Dodecaspis trizonia, n. sp.

Radial spines thin, cylindrical in the longer inner half, conical in the shorter outer half. The four meshes of each equatorial and each polar plate of equal size, roundish or nearly circular, five to six times as broad as the bars. By-spines straight, denticulated, scarcely half as long as the radius.

Dimensions.--Diameter of the shell 0.12, of the parmal pores 0.012.

Habitat.--South-west Pacific (east coast of New Zealand), Station 169, surface.

B. Tribe II. #Lychnaspida#, Haeckel, 1881, Prodromus, p. 467.

Definition.--#Dorataspida# with twenty perforated plates or fenestrated shields (each plate at least with four pores), produced by union of the branches of the four crossed apophyses, which arise, opposite in pairs, from each radial spine. The spherical shell is composed of the twenty plates united by sutures (rarely by concrescence).

Genus 362. Tessaraspis,[402] Haeckel, 1881, Prodromus, p. 468.

Definition.--#Dorataspida# with twenty plates, which are perforated by eighty aspinal pores (four crossed pores in each plate). Surface smooth, without by-spines.

The genus Tessaraspis introduces the series of Lychnaspida, which comprise all those Dorataspida in which the shell is composed of twenty plates, each of which is perforated by four primary aspinal pores. In Tessaraspis and Lychnaspis each plate exhibits only these four primary pores, whilst in Icosaspis and Hylaspis they become surrounded by a circle of secondary or coronal pores. If in Stauraspis, the common ancestral form of the Tessaraspida, the four crossed apophyses of each single radial spine became recurved and united together, we should have the typical plate of Tessaraspis, in which the piercing radial spine is surrounded by four crossed pores of equal size. The number of sutural pores, between the neighbouring plates, is variable; usually each plate is surrounded by a circle of eight to twelve sutural pores. The sutures between the meeting condyles of the apophyses usually remain open; but in some species they become obliterated (subgenus Tessaraspidium).

Subgenus 1. Tessarasparium, Haeckel.

Definition.--Condyles of the neighbouring plates connected by permanent open sutures; therefore the whole shell is composed of twenty separated pieces of acanthin.

{836}1. Tessaraspis arachnoides, n. sp. (Pl. 136, fig. 1).

Parmal pores pentagonal, ten to twenty times as broad as the thin thread-like bars, on an average of about the same size as the irregular sutural meshes; the majority of the latter are either triangular or hexagonal. Radial spines very thin and long, cylindrical, their outer part two to four times as long as the inner. As the insertion of the spines is on the highest point of the plates, the shell becomes polyhedral (dodecahedral?).

Dimensions.--Diameter of the shell 0.15 to 0.17, of the parmal meshes 0.02 to 0.025, sutural meshes 0.01 to 0.03, bars 0.002.

Habitat.--Equatorial Atlantic, Station 347, surface.

2. Tessaraspis pentagonalis, n. sp.

Parmal meshes pentagonal, three to four times as broad as the thick bars, and on an average smaller than the irregular polygonal sutural meshes. Radial spines stout, quadrangular; their outer pyramidal part shorter than the inner prismatic part.

Dimensions.--Diameter of the shell 0.12, of the parmal pores 0.01 to 0.012, bars 0.003.

Habitat.--Central Pacific, Station 269, surface.

3. Tessaraspis tetragonalis, n. sp.

Parmal meshes tetragonal, or nearly square, six to eight times as broad as the thin bars, and on an average larger than the irregular polygonal sutural meshes. Radial spines thin, quadrangular, prismatic, their outer part longer than their inner.

Dimensions.--Diameter of the shell 0.16, of the parmal pores 0.012 to 0.016, bars 0.002.

Habitat.--South Pacific, Station 288, surface.

4. Tessaraspis hexagonalis, n. sp.

Parmal meshes hexagonal, ten to twelve times as broad as the thin bars, and on an average larger than the polygonal sutural meshes (the two proximal sides of each hexagonal parmal mesh two to three times as long as the four distal sides). Radial spines cylindrical, thin; their outer part longer than the inner.

Dimensions.--Diameter of the shell 0.15, of the parmal pores 0.01 to 0.015, bars 0.001.

Habitat.--North Pacific, Station 254, surface.

5. Tessaraspis trigonalis, n. sp.

Parmal meshes triangular, three to four times as broad as the thick bars, and on an average smaller than the irregular sutural meshes (in each plate all four parmal meshes of the same size, formed like an isosceles triangle, the distal base of which is somewhat curved, and convex towards {837}the periphery, whilst the two proximal sides are straight). Radial spines thick, rounded; their outer conical part shorter than the inner cylindrical part.

Dimensions.--Diameter of the shell 0.1, of the parmal pores 0.01, of the sutural pores 0.01 to 0.02.

Habitat.--Tropical Atlantic (near Ascension), Station 345, depth 2010 fathoms.

6. Tessaraspis circularis, n. sp.

Parmal meshes circular, all eighty of equal size, quite regular, five to six times as broad as the thick bars, on an average larger than the roundish irregular sutural meshes. Radial spines quadrangular, prismatic, the outer part longer than the inner.

Dimensions.--Diameter of the shell 0.18, parmal pores 0.015 to 0.018, bars 0.003.

Habitat.--South-east Pacific, Station 300, surface.

7. Tessaraspis micropora, n. sp.

Parmal meshes circular, very small, all eighty of the same size, regular, scarcely as broad as the separating thick bars, and much smaller than the large irregular sutural meshes. Radial spines rounded, their outer conical part about as long as the inner cylindrical part.

Dimensions.--Diameter of the shell 0.08, of the parmal pores 0.003, of the sutural pores 0.005 to 0.015, bars 0.004.

Habitat.--Western Tropical Pacific, Station 225, surface.

8. Tessaraspis diodon, Haeckel.

Dorataspis diodon, Haeckel, 1862, Monogr. d. Radiol., p. 417, Taf. xxii. figs. 1-5.

Parmal meshes roundish, for the most part nearly circular, three to four times as broad as the bars, and on an average smaller than the roundish sutural meshes. Radial spines in the inner part cylindrical; the outer part very short (only one-third or one-fourth of the radius), divided completely into two parallel conical pointed teeth by a deep incision.

Dimensions.--Diameter of the shell 0.12, of the parmal pores 0.01 to 0.012, of the sutural pores 0.01 to 0.03, bars 0.004.

Habitat.--Mediterranean (Messina), surface.

9. Tessaraspis quadriforis, n. sp.

Parmal meshes irregular, roundish, of nearly equal size, four to six times as broad as the bars, and on an average of the same size as the roundish sutural meshes. Radial spines quadrangular, prismatic in the inner part, which is somewhat longer than the conical outer part.

Dimensions.--Diameter of the shell 0.16, of the pores 0.012 to 0.018, bars 0.003.

Habitat.--North Atlantic, Canary and Cape Verde Islands, Station 353, surface.

{838}10. Tessaraspis irregularis, n. sp.

Parmal meshes irregular, roundish, of unequal size, three to six times as broad as the bars, and on an average larger than the irregular sutural meshes. Radial spines cylindrical, the outer part longer than the inner part.

Dimensions.--Diameter of the shell 0.13, parmal pores 0.006 to 0.012, sutural pores 0.005 to 0.01; bars 0.002.

Habitat.--Central Pacific, Station 270, surface.

Subgenus 2. Tessaraspidium, Haeckel.

Definition.--Condyles of the neighbouring plates grown together and sutures obliterated; therefore the whole shell forms a single piece of acanthin.

11. Tessaraspis quadrata, n. sp.

Tessaraspidium quadratum, Haeckel, 1882, Manuscript.

Parmal meshes square, four times as broad as the thin bars, on an average of the same size as the polygonal sutural meshes. Radial spines stout, tetrapterous, prismatic, in the outer part longer than in the inner. Sutures of the shell completely obliterated, therefore the whole shell forms one piece.

Dimensions.--Diameter of the shell 0.16, of the parmal pores 0.012, sutural pores 0.01 to 0.015.

Habitat.--South Atlantic, Station 332, depth 2200 fathoms.

12. Tessaraspis rotunda, n. sp.

Parmal meshes circular, of equal size, twice as broad as the thick bars, on an average smaller than the roundish sutural meshes. Radial spines cylindrical in the inner part, which is somewhat longer than the outer conical part. Sutures of the shell completely obliterated, therefore the whole shell forms one piece.

Dimensions.--Diameter of the shell 0.12, parmal pores 0.008, sutural pores 0.005 to 0.015.

Habitat.--North Atlantic, Station 354, surface.

13. Tessaraspis concreta, n. sp. (Pl. 136 fig. 5).

Parmal meshes irregular, polygonal or roundish, six to eight times as broad as the narrow and high bars, much larger than the irregular sutural meshes. Radial spines leaf-shaped, compressed, two-edged, pointed at both ends; inner and outer part nearly of equal size. Shell very thick walled; meshes therefore funnel-shaped; sutures completely obliterated, therefore the whole shell forms a single piece.

Dimensions.--Diameter of the shell 0.09, parmal pores 0.02, sutural pores 0.01.

Habitat.--Central Pacific, Station 274, depth 2750 fathoms.

{839}Genus 363. Lychnaspis,[403] Haeckel, 1862, Prodromus, p. 468.

Definition.--#Dorataspida# with twenty plates, which are perforated by eighty aspinal pores (four crossed pores in each plate). Surface covered with numerous by-spines.

The genus Lychnaspis, the largest and most common of all Dorataspida, exhibits the same structure of the shell as its ancestral form Tessaraspis, and differs from it only in the development of by-spines on the sutural condyles. Many species of this genus are very widely distributed, and appear in large numbers, and some of them are amongst the most graceful and elegant of the Radiolaria.

Subgenus 1. Lychnasparium, Haeckel.

Definition.--Condyles of the neighbouring plates connected by permanent open sutures; therefore the whole shell is composed of twenty separate pieces of acanthin.

1. Lychnaspis giltschii, n. sp. (Pl. 135, fig. 3).

Parmal meshes pentagonal, about ten or twelve times as broad as the thin bars, on an average of the same size as the irregular polygonal sutural meshes. By-spines (two hundred to three hundred) very delicate, half as long as the radius, barbed, and zigzag. Radial main-spines very thin and long, straight, cylindrical; their outer part longer than the inner part.

Dimensions.--Diameter of the shell 0.2, of the parmal pores 0.02, sutural pores 0.01 to 0.03, bars 0.002.

Habitat.--Tropical Atlantic, Stations 338 to 348, surface.

2. Lychnaspis capillaris, n. sp.

Parmal meshes pentagonal, twenty to thirty times as broad as the very thin thread-like bars, on an average of the same size as the irregular polygonal sutural meshes. By-spines (two hundred to two hundred and fifty) very delicate, zigzag, with very small denticles, one-third as long as the radius. Radial main-spines very thin and long, cylindrical, more or less undulated.

Dimensions.--Diameter of the shell 0.25, parmal pores 0.025, sutural pores 0.02 to 0.04, bars 0.001.

Habitat.--North Pacific, Station 250, surface.

3. Lychnaspis maxima, n. sp.

Parmal meshes pentagonal, six to eight times as broad as the thick bars, for the most part larger than the irregular sutural meshes. By-spines (four hundred to five hundred) nearly as {840}long as the radius, zigzag, with short denticles. Radial spines very long and stout, quadrangularly-prismatic, with four smooth edges.

Dimensions.--Diameter of the shell 0.3, parmal pores 0.03, sutural pores 0.01 to 0.025, bars 0.004.

Habitat.--Central Pacific, Stations 271 to 274, surface.

4. Lychnaspis serrata, n. sp.

Parmal meshes pentagonal, three to four times as broad as the thick bars, smaller than the irregular sutural meshes. By-spines (two hundred to three hundred) scarcely one-third as long as the radius, zigzag, with strong denticles. Radial spines very long, stout, quadrangularly-prismatic, with four serrated edges.

Dimensions.--Diameter of the shell 0.22, parmal pores 0.015, sutural pores 0.012 to 0.03, bars 0.004.

Habitat.--South Atlantic, Station 330, surface.

5. Lychnaspis wagenschieberi, n. sp.

Parmal meshes tetragonal, nearly rhombic, three to four times as broad as the thick bars, smaller than the large irregular sutural meshes. By-spines (about two hundred) large, as long as the radius, with long recurved denticles, very zigzag. Radial main-spines very long, four-sided prismatic. This species differs by the form and size of the spines, and by the square form of the parmal pores from the similar Lychnaspis polyancistra, of which the late excellent engraver Wagenschieber, of Berlin, has given such a beautiful figure in my monograph (Taf. xxi. fig. 8).

Dimensions.--Diameter of the shell 0.16, parmal pores 0.014, sutural pores 0.015 to 0.02, bars 0.004.

Habitat.--Central Pacific, Station 266, surface.

6. Lychnaspis polyancistra, Haeckel.

Dorataspis polyancistra, Haeckel, 1862, Monogr. d. Radiol., p. 418, Taf. xxi. figs. 7-9.

Parmal meshes roundish, tetragonal, or nearly square, two to three times as broad as the thick bars, smaller than the irregular sutural meshes. By-spines (about two hundred) thin, half as long as the radius, zigzag, with blunt denticles. Radial main-spines stout, in the inner half cylindrical, in the outer half (of the same length) conical, pointed.

Dimensions.--Diameter of the shell 0.12, parmal pores 0.012, sutural pores 0.01 to 0.04, bars 0.004.

Habitat.--Mediterranean (Messina), surface.

{841}7. Lychnaspis rottenburgii, n. sp. (Pl. 135, fig. 4).

Parmal meshes roundish, about twice as broad as the thick bars, and for the most part smaller than the irregular sutural meshes. By-spines (about two hundred to two hundred and fifty) thin, zigzag, half as long as the radius. Radial main-spines very strong, cylindrical in the inner half, in the outer half much thicker and conical, pointed. I call this species in honour of my learned friend, the great patron of zoological studies, Mr. Paul Rottenburg, of Glasgow.

Dimensions.--Diameter of the shell 0.15, parmal pores 0.012, sutural pores 0.01 to 0.03, bars 0.006.

Habitat.--Central Pacific, Station 270, depth 2925 fathoms.

8. Lychnaspis undulata, n. sp. (Pl. 135, fig. 2).

Parmal meshes circular, twice as broad as the thick bars, on an average of the same size as the irregular sutural meshes. By-spines (one hundred and fifty to two hundred) very thin, barbed and zigzag, as long as the radius. Radial main-spines cylindrical; their outer pointed part longer than the inner part.

Dimensions.--Diameter of the shell 0.1, parmal pores 0.01, sutural pores 0.01, bars 0.005.

Habitat.--Tropical Atlantic, Station 343, surface.

9. Lychnaspis longissima, n. sp. (Pl. 134, fig. 6).

Parmal meshes circular, very small, of the same breadth as the thick bars, much smaller than the irregular sutural meshes. By-spines (one hundred to one hundred and ten) very long and thin, zigzag, twice as long as the diameter of the shell. Radial main-spines very long and strong, cylindrical (at the base quadrangular, pyramidal), four to six times as long as the diameter of the shell, and one fourth as thick as its radius.

Dimensions.--Diameter of the shell 0.08, parmal pores 0.002, sutural pores 0.01 to 0.015, bars 0.003; length of the radial spines 0.3 to 0.5.

Habitat.--Tropical Pacific (Philippines), Stations 200 to 215, surface.

10. Lychnaspis minima, n. sp. (Pl. 134, figs. 2, 7, 8).

Parmal meshes circular, very small, only half as broad as the thick bars, much smaller than the irregular sutural meshes. By-spines (one hundred to one hundred and ten) half as long as the radius, zigzag. Radial main-spines thick, in the inner part cylindrical, in the outer shorter part conical, of very variable size.

Dimensions.--Diameter of the shell 0.05, parmal pores 0.002, sutural pores 0.006 to 0.012, bars 0.004.

Habitat.--Antarctic Ocean, Station 154, surface.

{842}Subgenus 2. Lychnaspidium, Haeckel.

Definition.--Condyles of the neighbouring plates grown together and sutures obliterated, therefore the whole shell forms a single piece of acanthin.

11. Lychnaspis echinoides, Haeckel.

Haliomma echinoides, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p.36, Taf. v. figs. 3, 4.

Haliommatidium echinoides, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 22.

Haliommatidium echinoides, Haeckel, 1862, Monogr. d. Radiol., p. 422.

Parmal meshes pentagonal or somewhat roundish, four times as broad as the bars, and of about the same size as the polygonal meshes. By-spines (about two hundred) short, zigzag. Radial spines thin; their outer conical part shorter than the inner cylindrical part. Sutures perfectly obliterated, but recognisable by the characteristic pair of divergent by-spines. (Some recent observations on this species, made during 1880 in Portofino, have convinced me that the interpretation of it given in my Monograph, 1862, loc. cit., was quite correct.)

Haliomma ligurinum, J. Müller (= Haliommatidium ligurinum, Haeckel, L. N. 16, p. 423) seems to be closely allied to the preceding.

Dimensions.--Diameter of the shell 0.12 to 0.14, parmal pores 0.015, sutural pores 0.01 to 0.02, bars 0.004.

Habitat.--Mediterranean, Nice, Saint Tropez (J. Müller); Portofino near Genoa (Haeckel).

12. Lychnaspis haliommidium, n. sp.

Lychnaspidium haliommidium, Haeckel, 1882, Manuscript.

Parmal meshes circular, twice as broad as the bars, smaller than the irregular sutural meshes. By-spines (about two hundred) barbed and zigzag, as long as the radius. Radial main-spines four-sided; their outer pyramidal part shorter than the inner prismatic part. Sutures perfectly obliterated.

Dimensions.--Diameter of the shell 0.1, parmal pores 0.01, sutural meshes 0.015 to 0.02.

Habitat.--South Atlantic, Station 335, depth 1425 fathoms.

13. Lychnaspis rabbeana, n. sp.

Parmal meshes circular, very small, of the same breadth as the bars, and much smaller than the irregular sutural meshes. By-spines (about one hundred) very long and thin, zigzag, about as long as the diameter of the shell. Radial main-spines cylindrical, thick, twice to three times as long as the diameter of the shell. Sutures perfectly obliterated, with thickened condyles. Named in honour of Captain Henrik Rabbe (of Bremen), to whom I am indebted for many new Indian and Atlantic Radiolaria.

Dimensions.--Diameter of the shell 0.086, parmal pores 0.002, sutural pores 0.012, bars 0.002.

Habitat.--Indian Ocean (Madagascar), Rabbe, surface.

{843}14. Lychnaspis cataplasta, n. sp.

Parmal pores very small, circular, half as broad as the bars, and much smaller than the irregular sutural pores. By-spines zigzag, as long as the diameter of the shell. Radial main-spines very thin and long, needle-shaped, cylindrical, five to six times as long as the diameter of the shell. Sutures perfectly obliterated. (This stunted species is one of the smallest of the Dorataspida.)

Dimensions.--Diameter of the shell 0.05, parmal pores 0.0015, sutural pores 0.01, bars 0.002.

Habitat.--Antarctic Ocean (off Kerguelen Island), Station 149, surface.

Genus 364. Icosaspis,[404] Haeckel, 1881, Prodromus, p. 468.

Definition.--#Dorataspida# with twenty plates, which are perforated by one hundred and sixty to three hundred or more parmal pores (in each plate four crossed aspinal pores, and around them four to twelve or more coronal pores). Surface without by-spines.

The genus Icosaspis and the closely allied Hylaspis differ from all other Tessaraspida in the increased number of the parmal pores. Whilst this number in all other genera is eighty (only four crossed pores in each plate), here it amounts to one hundred and sixty to three hundred or more (sometimes more than a thousand); in each shield four primary, crossed "aspinal pores" being surrounded by a circle of four to twelve or more "coronal pores." The number of sutural pores in these two genera is also increased.

Subgenus 1. Icosasparium, Haeckel.

Definition.--Condyles of the neighboring plates connected by permanent open sutures; therefore the whole shell composed of twenty separated pieces of acanthin.

1. Icosaspis tabulata, n. sp. (Pl. 136, fig. 2).

Parmal meshes all of nearly equal size and form, square, four times as broad as the bars, little larger than the triangular or polygonal sutural meshes. In each plate fifty to seventy (regularly sixty-four) quadrangular pores, viz., four primary square aspinal meshes, forming together a regular square surrounded by two to three coronas of rectangular (not quite regular) coronal meshes (six to eight in each transverse row). Radial spines tetrapterous, prismatic, with four thin and broad wings, from which arise the crossed bars between the four primary pores. Outer part of the spines longer than the inner. Commonly the condyles of the plates are only contiguous; sometimes they grow together, and this form approaches Icosaspis tetragonopa.

Dimensions.--Diameter of the shell 0.25 to 0.3, of the pores 0.02, bars 0.005.

Habitat.--North Pacific, Station 244, depth 2900 fathoms.

{844}2. Icosaspis elegans, n. sp. (Pl. 136, fig. 4; Pl. 134, fig. 9).

Tessaraspis elegans, Haeckel, 1882, Manuscript et Atlas.

Parmal meshes of very different size and form; in the centre of each plate a cross of four primary, pear-shaped "aspinal pores" (the largest of all); between them four secondary, little smaller, crossed, egg-shaped "angular pores"; around this rosette of eight larger meshes an inner complete circle of sixteen to twenty polygonal coronal pores, and an outer incomplete circle of thirty to forty very small marginal pores. The latter are smaller than the irregular sutural meshes, which are constricted in the middle, about forty to sixty around each plate. Radial spines thin, cylindrical, or a little compressed; their outer part longer than the inner. In this elegant and very common species the condyles usually remain separated by sutures; but sometimes the latter become obliterated, and the whole shell then forms a single piece, Icosaspidium elegans.

Dimensions.--Diameter of the shell 0.2 to 0.3, commonly 0.25; larger parmal pores 0.02, smaller 0.001 to 0.003; sutural pores 0.005 to 0.015; bars 0.003.

Habitat.--Tropical and Subtropical Atlantic, Canary Islands to Ascension Island, Stations 340 to 354, surface.

3. Icosaspis cruciata, n. sp. (Pl. 134, fig. 10).

Parmal meshes very different; in the centre of each plate a cross of four primary, nearly oblong, rectangular "aspinal pores"; between these four secondary, triangular, egg-shaped "angular pores" (the largest of all), and around this rosette a single circle of twelve to twenty-four small "coronal pores." The latter are of about the same size as the irregular sutural meshes, of which there are twenty to thirty around each plate. Radial spines thin, cylindrical, or a little compressed; their outer part longer than the inner.

Dimensions.--Diameter of the shell 0.2 to 0.3, commonly 0.25; larger parmal pores 0.025, smaller 0.005 to 0.01; bars 0.005.

Habitat.--Tropical and Subtropical Pacific, Sandwich to Marquesas Islands, Stations 256 to 274, surface.

4. Icosaspis ornata, n. sp.

Parmal meshes very different; in the centre of each plate a cross of four primary octagonal aspinal pores (the largest of all); between them four secondary, rhombic angular pores, and around this rosette a circle of twelve to sixteen smaller, polyhedral coronal pores, which are however larger than the irregular sutural pores (surrounding each plate to the number of twenty to thirty). Radial spines thin, quadrangular, prismatic; the outer part longer than the inner.

Dimensions.--Diameter of the shell 0.25; larger parmal pores 0.03, smaller 0.01; sutural pores 0.004 to 0.008; bars 0.006.

Habitat.--South Pacific, Station 295, depth 1500 fathoms.

{845}5. Icosaspis spectabilis, n. sp.

Parmal meshes very different; in the centre of each plate four very large, pentagonal aspinal pores, and around these two to three circles of smaller polygonal coronal pores, which are very numerous, and not larger than the small sutural pores. Radial spines quadrangular, prismatic, stout, very long; the outer part two to three times as long as the inner.

Dimensions.--Diameter of the shell 0.4, of the larger aspinal meshes 0.03, of the outer meshes 0.002 to 0.02, bars 0.005.

Habitat.--South Atlantic, Station 333, surface.

6. Icosaspis multiforis, n. sp.

Parmal meshes very numerous, more than one hundred in each plate; in the centre four larger pear-shaped pores, and around these four to five circles of smaller pores, gradually smaller towards the margin of the plate; the sutural meshes also very small and numerous (more than fifty around each plate), so that the number of all the pores together amounts to two thousand or even more. Radial spines thin, cylindrical, very long.

Dimensions.--Diameter of the shell 0.32; larger aspinal pores 0.02, smaller 0.002 to 0.01; bars 0.003.

Habitat.--Indian Ocean (Madagascar), Rabbe, surface.

Subgenus 2. Icosaspidium, Haeckel.

Definition.--Condyles of the neighbouring plates grown together, and sutures obliterated; therefore the whole shell forms a single piece of acanthin.

7. Icosaspis tetragonopa, Haeckel.

Haliommatidium tetragonopum, Haeckel, 1862, Monogr. d. Radiol., p.421, Taf. xxii. fig. 13.

Parmal meshes all of nearly equal size and form, square, three times as broad as the bars, little larger than the sutural meshes. In each plate commonly sixteen equal square meshes, viz., four primary aspinal and twelve secondary, surrounding the former as a square corona. Radial spines tetrapterous, stout; the outer pyramidal half somewhat longer than the inner. This species differs from the similar Icosaspis tabulata (Pl. 136, fig. 2) in the concrescence of the sutures, the smaller number of pores, and the form of the stouter spines. The figure in my Monograph, drawn from a broken fragment, is not quite correct.

Dimensions.--Diameter of the shell 0.18, pores 0.009, bars 0.003.

Habitat.--Mediterranean (Messina, Corfu), surface.

8. Icosaspis icosahedra, n. sp.

Parmal meshes of different size and form; in the centre of each plate a cross of four pentagonal, primary aspinal pores, surrounded by a complete corona of twelve to sixteen polygonal coronal {846}pores and an incomplete corona of thirty to forty very small marginal pores; the latter are not to be distinguished from the pores of the obliterated sutures. Radial spines quadrangular, the outer pyramidal part shorter than the inner prismatic part. Condyles grown together. As the plates are quite even, the shell becomes icosahedral.

Dimensions.--Diameter of the shell 0.16, pores 0.002 to 0.02, bars 0.005.

Habitat.--North Pacific, Station 241, surface.

9. Icosaspis icosastaura, n. sp. (Pl. 136, fig. 3).

Tessaraspis icosastaura, Haeckel, 1882, Manuscript et Atlas.

Parmal plates of different size and form; in the centre of each plate a cross of four larger primary, pyriform aspinal pores; between these four smaller roundish angular pores, and around this rosette a circle of ten to twenty (commonly sixteen) coronal pores, little larger than the very small sutural pores. Radial spines very thin and long, cylindrical or bristle-shaped. Condyles grown together; no suture visible.

Dimensions.--Diameter of the shell 0.14; larger pores of the cross 0.01, smaller pores 0.002 to 0.008; bars 0.002 to 0.004.

Habitat.--Central Pacific, Station 268, surface.

Genus 365. Hylaspis,[405] n. gen.

Definition.--#Dorataspida# with twenty plates, which are perforated by one hundred and sixty to three hundred or more parmal pores (in each plate four crossed aspinal pores, and around them four to twelve or more coronal pores). Surface covered with numerous by-spines.

The genus Hylaspis exhibits the same structure of the shell as the nearly allied ancestral genus Icosaspis, and differs from it only in the development of by-spines. Some species of these two genera exhibit the highest degree of complication in the structure of the shell seen among the Dorataspida.

1. Hylaspis serrulata, n. sp. (Pl. 135, fig. 1).

Parmal meshes four hundred to five hundred; in the centre of each plate a cross of four very large pentagonal or roundish aspinal pores, and around this a circle of sixteen to twenty much smaller irregular, polygonal, coronal pores; the latter of about the same size as the sutural pores. On each condyle one thin zigzag-shaped by-spine, nearly as long as the radius. Twenty radial spines very long, quadrangular, prismatic; on the inside thinner and smooth, on the outside thickened, and armed with four rows of recurved teeth, serrated.

Dimensions.--Diameter of the shell 0.18, aspinal spines 0.02, other pores 0.002 to 0.01, bars 0.003.

Habitat.--South Atlantic, Station 326, surface.

{847}2. Hylaspis coronata, n. sp.

Parmal meshes five hundred to six hundred; in the centre of each plate a cross of four long rectangular aspinal pores, between these four larger egg-shaped angular pores; around this rosette a circle of sixteen to twenty much smaller, irregular, roundish, coronal pores; the latter about of the same size as the sutural pores. On each condyle one bearded by-spine about one-third or one-fourth as long as the radius. Twenty radial spines, very long, smooth, quadrangular, prismatic.

Dimensions.--Diameter of the shell 0.25, aspinal pores 0.02, other pores 0.005 to 0.01, bars 0.004.

Habitat.--Central Pacific, Station 271, surface.

3. Hylaspis barbata, n. sp.

Parmal meshes twelve hundred to sixteen hundred; in the centre of each plate a cross of four large, somewhat oblong, octahedral aspinal pores, between these four rhombic smaller angular pores; around this rosette an inner circle of twelve to sixteen larger and an outer circle of fifty to sixty very small coronal pores; the latter smaller than the sutural pores. On each condyle one bristle-shaped zigzag by-spine, with recurved thin hooks, half as long as the radius. Twenty radial spines, very long, cylindrical, smooth.

Dimensions.--Diameter of the shell 0.25 to 0.3, aspinal pores 0.022, other pores 0.002 to 0.015, bars 0.002.

Habitat.--South Pacific, Station 295, surface.

Family XLI. #PHRACTOPELTIDA#, Haeckel (Pl. 133, figs. 1-6).

Phractopeltida, Haeckel, 1881, Prodromus, p. 468.

Definition.--ACANTHARIA with double spherical lattice-shell, composed of the branched apophyses of twenty radial spines meeting in its centre, and disposed according to the Müllerian law of Icosacantha. Central capsule spherical, enclosing the inner and surrounded by the outer concentric shell.

The family #Phractopeltida# differs from all other ACANTHARIA in the development of a double spherical shell, composed of two concentric lattice-spheres, which are united by twenty radial spines meeting in the common centre. We could therefore oppose the Phractopeltida as Diplophracta to all other #Acanthophracta# as Haplophracta (with simple shell). The former exhibit a relation to the latter, similar to that exhibited by the Dyosphærida to the simple Monosphærida among the #Sphæroidea#.

In my Monograph (1862, p. 423) I described only one genus appertaining to this family, Aspidomma. I founded it upon the singular Phractopelta, described by {848}J. Müller as Haliomma hystrix. A second species of Aspidomma, the Acanthometra mucronata of J. Müller, was probably an Astrolonche. At that time I placed Aspidomma among the Haliommatida, led by the erroneous opinion that it might represent a transition-form between Dorataspis and Haliomma. But I afterwards gave up this view, as I was convinced that there is no true phylogenetic connection between the acanthinic Dorataspida (Actipylea) and the siliceous Haliommatida (Peripylea). Therefore in my Prodromus (1881, p. 468) I placed Aspidomma among the Dorataspida and changed its name to Phractopelta, to avoid further confusion with the unrelated Ommatida (#Sphæroidea#). It formed there, with three nearly related genera, the "subfamily Phractopeltida," which we now advance to the higher rank of a separate family. (By a typographical mistake the words are printed in the Prodromus Phractopelma and Phractopelmida, &c., instead of Phractopelta and Phractopeltida, &c.). The detection of other new species appertaining to this family, and a closer anatomical investigation of them, has now led to the distinction of five different genera, characterised by other differences than were employed in 1881 in the provisional system of the "Prodromus."

The two concentric spherical lattice-shells of the Phractopeltida, connected by radial beams, correspond perfectly to those of the double-shelled Dyosphærida (Haliomma, Diplosphæra, &c.), and in both cases we may call the smaller inner the "medullary shell," and the larger outer the "cortical shell." There is no doubt that the double-shelled Phractopeltida must be derived phylogenetically from the simple-shelled Dorataspida (just as we derive the double Dyosphærida from the simple Monosphærida). But it is not yet possible to decide positively which of the two shells is the first formed. Probably the small inner or medullary shell of the Phractopeltida is the first formed, and corresponds to the simple spherical lattice-shell of the Dorataspida; and the larger outer or cortical shell of the former is a later new formation, absent in the latter family. This opinion seems to be confirmed by the genus Orophaspis, the only form among the Dorataspida, in which the radial spines outside the shell bear free latticed apophyses. If these twenty apophyses grow further and meet one another, the second or outer shell of Phractopelta may be formed. But some objections may be raised to this opinion from the peculiar structure and the very small size of the inner shell; and there is some possibility that this latter is a secondary later product inside of the primary cortical shell. The probably phylogenetic series which reveals the origin of the Phractopeltida is the following:--Acanthometron, Zygacantha, Lithophyllium, Phractacantha, Doracantha, Dorataspis, Orophaspis, Phractopelta.

The twenty radial spines exhibit in all Phractopeltida the same characteristic position and relation as in all other Icosacantha, and are constantly arranged according to the Müllerian law in four meridian planes, their distal ends falling into five parallel zones. Their distinction in the majority of the Phractopeltida is not difficult, {849}since the spines of the different zones bear apophyses of different shapes. Sometimes the four equatorial spines are stouter than the sixteen other spines, and often the eight tropical spines are somewhat different in form from the eight polar and from the four equatorial spines. The length of all twenty spines is commonly equal. Their form is usually more or less compressed, two-edged (as in Zygacantha), more rarely cylindrical (as in Acanthometron), or somewhat quadrangular (but not truly prismatic); therefore the transverse section of the spines is commonly elliptical or lanceolate, rarely circular or rhombic, never square; this seems to indicate their origin from Zygacantha. As in all ACANTHARIA, the spines consist of acanthin, not of silex. Their central ends are either perfectly grown together, and form a single star of acanthin, or the triangular faces of their small pyramidal bases are supported one upon another, without true concrescence.

The apophyses of the radial spines, by which the two concentric spherical shells are formed, seem to be constantly four on each spine, two being opposite in each shell. The proximal pair of opposite apophyses, forming the inner or medullary shell, is constantly much smaller than the distal pair composing the outer or cortical shell (Pl. 133, fig. 5). The proximal pair corresponds probably to the two primary apophyses of the Diporaspida (Phractaspis, Dorataspis, &c.), whilst the distal pair corresponds to the free apophyses of Orophaspis (Pl. 133, fig. 6). Therefore the Phractopeltida may be derived phylogenetically from the Diporaspida (not from the Tessaraspida). In the common ancestral genus of this family, Phractopelta, the free part of the radial spines (outside the outer shell) is quite simple, without free apophyses; in all other genera of the family that free part of the spines (either in all twenty spines or only in some of them) bears a third pair of lateral apophyses; these may be either simple or branched or even latticed; but the outer apophyses (of the third rank) remain constantly free, and a third lattice-shell is never formed by union of their edges (Pl. 133, figs. 2-4).

The inner lattice-shell of the Phractopeltida, or their "medullary shell," is constantly very small (commonly 0.03 to 0.05 mm. in diameter, rarely more). Its structure is difficult to make out; in the unbroken shell it is concealed by the dense network of the outer shell; in the broken shell it is commonly destroyed. Usually the pores of the inner shell are very small, circular or subcircular, scarcely as broad as the small separating bars. In the majority of Phractopeltida their number seems to be about forty, being probably the forty primary aspinal pores of the Diporaspida; in some species this number seems to be exceeded, so that perhaps some sutural pores may exist between the aspinal pores; but commonly the twenty plates composing the inner shell (each with two aspinal pores) seems to grow together perfectly by their meeting edges, so that there are no sutural pores between them. Evident sutures were not recognisable in the inner shell of any Phractopeltida.

{850}The outer lattice-shell of the Phractopeltida, or their "cortical shell," is at least twice as broad, commonly about three times as broad, as the enclosed inner shell; it is much more varied in composition than the latter. Like the greater part of the Dorataspida we may distinguish here in the lattice-work two kinds of pores--parmal pores and sutural pores. The parmal pores are produced by the union of the meeting branches of the apophyses of each single spine, and are therefore visible on each isolated spine; whilst the sutural pores are formed by the meeting branches of the apophyses of neighbouring spines. The distinction of the parmal and the sutural pores, easy in most Dorataspida, is difficult in most Phractopeltida, because the sutures between the meeting branches are usually very early obliterated. However, the place of the obliterated suture is often indicated by the thickened condyles of the apophyses on both sides of the suture. Commonly also the form of the sutural pores is much more irregular than that of the parmal pores; the former are more or less constricted in the middle by the intumescence of the sutural condyles, whilst the latter are more roundish, elliptical, kidney-shaped, or square. The number of the pores in the outer shell in the typical normal form of Phractopeltida seems to be the same as in the most species of Dorataspis, Diporaspis, &c., between ninety and one hundred, viz., forty parmal pores and from fifty to sixty sutural pores. However, in many species this number is increased. Since in all Phractopeltida, each of the twenty plates is composed only of the meeting branches of two opposite apophyses, we find originally in each plate only two primary parmal pores or "aspinal pores." But in some species there occur four, six, or more pores in each plate; in this case two of them only are aspinal pores, all the others being "coronal pores." Moreover, in those species which exhibit on the base of each spine in the outer shell four crossed pores (Pl. 133, fig. 2), there are not four equivalent aspinal pores (as in the Tessaraspida), but the two opposite are primary or aspinal pores and the other two (different from them in size and form) coronal pores. However, the number of coronal pores in the Phractopeltida is never so large as in many Dorataspida, and the same holds good also for the increasing number of the irregular sutural pores. In none of the species observed does the total number of the pores in the outer shell reach two hundred.

The original mode of development of the apophyses composing the outer shell seems to be imitated by the free apophyses of the third order, which are developed from the radial spines outside the outer shell in all Phractopeltida, with the single exception of the simple ancestral genus Phractopelta. These apophyses of the third rank are also originally constantly two, opposite to one another (after the type of Lithophyllium, Dorataspis, &c.). Commonly they do not remain simple, but become branched, and by communication of the neighbouring branches small lattice-plates arise. Originally each of these free lattice-plates has only two parmal pores, but the number of the parmal pores increases afterwards, so that we may distinguish two (primary) {851}aspinal pores, and two, four, or more (secondary) coronal pores. In the majority of species the two opposite apophyses are first crossed at right angles by a transverse beam, and the two parallel transverse beams are again crossed by perpendicular tertiary branches (again parallel to the apophyses). In this case the network of the free lattice-plates becomes more or less rectangular. But in other species the ramification of the apophyses assumes more the form of bifurcation or of irregular branching. As already said, the neighbouring free lattice-plates of this third order never meet, and therefore a complete third shell is never formed.

The different genera of Phractopeltida exhibit very remarkable differences in the development of free apophyses (or lattice-plates of the third order). Whilst in the numerous species of the ancestral genus Phractopelta all twenty spines remain simple, without such apophyses, only in a single observed species (representing the genus Pantopelta) were all twenty spines protected by them. In the three other genera only one part of the spines bears free apophyses, but not the other part. The most frequent form is Dorypelta (Pl. 133, fig. 2); here eight spines are simple (four equatorial and four polar spines of the hydrotomical plane), whilst twelve spines bear apophyses (eight tropical and four polar spines of the geotomical plane). In Octopelta the eight tropical spines only bear apophyses, whilst the twelve other (four equatorial and eight polar) are simple. In Stauropelta finally the four equatorial spines only are simple, whilst the sixteen other bear free apophyses (eight tropical and eight polar spines).

The Central Capsule of the Phractopeltida is constantly spherical, and enclosed between the two concentric spherical shells; it is therefore larger than the inner and smaller than the outer shell. Its wall is pierced by the twenty radial beams connecting the two shells. The shape of the central capsule and of the enveloping calymma is the same as in the other #Acanthophracta# and specially in the Dorataspida.

Synopsis of the Genera of Phractopeltida.

{All twenty spines without { apophyses in the free All twenty spines of the { external part, 366. Phractopelta. same form, { {All twenty spines with { apophyses in the free { part, 367. Pantopelta.

{Eight tropical spines with { apophyses, twelve others { (eight polar and four { equatorial) simple, 368. Octopelta. { {Twelve radial spines Twenty radial spines, { (eight tropical and four partly without, partly { polar) with apophyses, with apophyses in the { eight others (four polar free external part, { and four equatorial) { simple, 369. Dorypelta. { {Sixteen radial spines { (eight tropical and { eight polar) with { apophyses, four { equatorial, simple, 370. Stauropelta.

{852}Genus 366. Phractopelta,[406] Haeckel, 1881, Prodromus, p. 468.

Definition.--#Phractopeltida# with twenty simple radial spines, bearing no free apophyses outside the outer shell.

The genus Phractopelta is the most simple form among the Phractopeltida, and may be regarded as the common ancestral form of this family. All twenty spines are of nearly equal form and size, and bear no free apophyses on their free part, outside the two concentric shells. Phractopelta may be derived from Orophaspis by further development of the free apophyses, which by union of their branches form a second outer shell around the primary shell of that Dorataspid.

Subgenus 1. Phractopeltaris, Haeckel.

Definition.--Outer shell composed of twenty separated plates, the sutures of their meeting condyles not being grown together.

1. Phractopelta dorataspis, n. sp. (Pl. 133, fig. 1).

Outer shell composed of twenty plates, the meeting condyles of which are separated by permanent sutures. Each plate commonly with two elliptical aspinal pores, which are two to three times as broad as the irregular sutural pores. Radial spines (in the outer free part) compressed, linear, twice as long as the diameter of the shell.

Dimensions.--Diameter of the outer shell 0.11, of the inner 0.05.

Habitat.--North Pacific (off Japan), Station 239, surface.

2. Phractopelta dyadopora, n. sp.

Outer shell composed of twenty plates, the meeting condyles of which are separated by permanent sutures. Each plate commonly with two kidney-shaped aspinal pores, which are three to four times as broad as the irregular sutural pores. Radial spines conical, about as long as the radius of the shell.

Dimensions.--Diameter of the outer shell 0.08, of the inner 0.04.

Habitat.--North Pacific, Station 256, surface.

3. Phractopelta diporaspis, n. sp.

Outer shell composed of twenty plates, the meeting condyles of which are separated by permanent sutures. Each plate commonly with two quadrangular aspinal pores, which are four to five times {853}as broad as the irregular sutural pores. Radial spines compressed, sword-shaped, about as long as the diameter of the shell.

Dimensions.--Diameter of the outer shell 0.09, of the inner 0.04.

Habitat.--South Atlantic, Station 332, surface.

4. Phractopelta tessaraspis, n. sp.

Outer shell composed of twenty plates, the meeting condyles of which are separated by permanent sutures. Each plate commonly with four crossed, quadrangular, aspinal pores, the two opposite of which are much larger than the two others. Sutural pores small, roundish. Radial spines compressed, linear, about twice as long as the diameter of the shell.

Dimensions.--Diameter of the outer shell 0.084, of the inner 0.032.

Habitat.--North Pacific (off Japan), Station 238, surface.

5. Phractopelta tetradopora, n. sp.

Outer shell composed of twenty plates, the meeting condyles of which are separated by permanent sutures. Each plate commonly with four crossed quadrangular (or nearly circular) aspinal pores, all of nearly the same size. Sutural pores polygonal or roundish. Radial spines cylindrical, two to three times as long as the diameter of the shell.

Dimensions.--Diameter of the outer shell 0.11, of the inner 0.045.

Habitat.--North Pacific, Station 253, surface.

6. Phractopelta hexadopora, n. sp.

Outer shell composed of twenty plates, the meeting condyles of which are separated by permanent sutures. Each plate commonly with six aspinal pores, the two opposite of which are much larger than the four others. Sutural pores small, roundish. Radial spines compressed, two-edged, larger than the diameter of the shell.

Dimensions.--Diameter of the outer shell 0.1, of the inner 0.04.

Habitat.--Central Pacific, Station 272, surface.

7. Phractopelta octadopora, n. sp.

Outer shell composed of twenty plates, the meeting condyles of which are separated by permanent sutures. Each plate commonly with eight aspinal pores, the four crossed being larger than the four others alternating with them. Sutural pores irregular. Radial spines conical, shorter than the diameter of the shell.

Dimensions.--Diameter of the outer shell 0.12, of the inner 0.04.

Habitat.--Indian Ocean (Cocos Islands, surface), Rabbe.

{854}Subgenus 2. Phractopeltidium, Haeckel.

Definition.--Outer shell composed of twenty united plates, the sutures of their meeting condyles being grown together.

8. Phractopelta aspidomma, n. sp.

Outer shell composed of twenty united plates, the meeting condyles of which are grown together. On the base of each radial spine (where its outer free part arises from the surface of the outer shell), two large elliptical aspinal pores, two to four times as large as the other roundish pores. Radial spines compressed, sword-shaped, about as long as the radius of the shell.

Dimensions.--Diameter of the outer shell 0.1, of the inner 0.05.

Habitat.--Equatorial Atlantic, Station 347, surface.

9. Phractopelta haliomma, n. sp.

Outer shell composed of twenty united plates, the meeting condyles of which are grown together. On the base of each radial spine two large kidney-shaped aspinal pores, little larger than the other irregular pores. Radial spines compressed, linear, two-edged, much longer than the diameter of the shell.

Dimensions.--Diameter of the outer shell 0.09, of the inner 0.03.

Habitat.--South Pacific, Station 295, surface.

10. Phractopelta tessaromma, Haeckel.

Outer shell composed of twenty united plates, the meeting condyles of which are grown together. On the base of each radial spine four crossed egg-shaped aspinal pores, two opposite of which are much larger than the two others. Sutural pores irregular. Radial spines cylindrical or little compressed, thin, longer than the diameter of the shell.

Dimensions.--Diameter of the outer shell 0.1, of the inner 0.04.

Habitat.--Central Pacific, Station 266, surface.

11. Phractopelta hystrix, Haeckel.

Haliomma hystrix, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 37, Taf. v. figs. 1, 2.

Aspidomma hystrix, Haeckel, 1862, Monogr. d. Radiol., p. 424.

Outer shell composed of twenty united plates, the meeting condyles of which are grown together. On the base of each radial spine four crossed circular aspinal spines of equal size. Sutural pores roundish, of about the same size. Radial spines conical, about as long as the radius of the shell.

Dimensions.--Diameter of the outer shell 0.07, of the inner 0.024.

Habitat.--Mediterranean (Nice), J. Müller, surface.

{855}Genus 367. Pantopelta,[407] n. gen.

Definition.--#Phractopeltida# with twenty radial spines, each of which is protected by two free external apophyses.

The genus Pantopelta differs from all other Phractopeltida in the development of free protecting apophyses on all twenty radial spines. Only a single specimen of this rare form was seen, and in this all twenty spines exhibited no marked differences in form and size, but were more or less irregularly developed.

1. Pantopelta icosaspis, n. sp. (Pl. 133, fig. 4).

Apophyses of all twenty radial spines with forked anastomosing branches, forming a more or less irregular cup-like fenestrated shield, pierced by a variable number of pores. Distance of the apophyses from the outer shell equal to half its radius. Pores of the outer shell irregular, roundish, four to six times as broad as those of the inner shell. Radial spines compressed, sword-shaped, longer than the radius of the shell.

Dimensions.--Diameter of the outer shell 0.08, of the inner 0.03.

Habitat.--Antarctic Ocean, Station 157, depth 1950 fathoms.

Genus 368. Octopelta,[408] n. gen.

Definition.--#Phractopeltida# with twelve simple spines (four equatorial and eight polar), and with eight tropical spines protected by external free apophyses.

The genus Octopelta differs from the other Phractopeltida in the possession of eight shields or pairs of free apophyses outside the outer lattice-shell; the spines bearing these apophyses are the eight tropical spines. The twelve other spines (eight polar and four equatorial) are quite simple, without apophyses.

1. Octopelta cultella, n. sp.

Apophyses of the eight tropical spines simple, compressed, knife-shaped, about as long as their distance from the outer shell. On the base of each spine (in the network of the outer shell) two orthogonal aspinal pores, two to three times as long as the other polygonal pores.

Dimensions.--Diameter of the outer shell 0.08, of the inner 0.03.

Habitat.--Tropical Atlantic, Station 338, surface.

{856}2. Octopelta furcella, n. sp.

Apophyses of the eight tropical spines forked, each with two parallel simple fork-branches, about as long as their distance from the outer shell. On the base of each spine (in the outer shell) two kidney-shaped aspinal pores, about twice as broad as the other irregular pores.

Dimensions.--Diameter of the outer shell 0.1, of the inner 0.04.

Habitat.--South Atlantic (off Tristan d'Acunha), Station 332, surface.

3. Octopelta scutella, n. sp. (Pl. 133, fig. 5).

Apophyses of the eight tropical spines crossed by a transverse beam, which is again crossed by two perpendicular branches; by union of these branches each tropical spine forms a square shield with four crossed pores and twelve to sixteen marginal spikes. On the base of each spine (in the surface of the outer shell) four crossed aspinal pores which correspond to those of the free shields; these are somewhat larger than the other pores.

Dimensions.--Diameter of the outer shell 0.12, of the inner 0.06.

Habitat.--Tropical Atlantic, Station 348, surface.

Genus 369. Dorypelta,[409] Haeckel, Prodromus, p. 369.

Definition.--#Phractopeltida# with eight simple spines (four equatorial and four hydrotomical polar spines) and with twelve spines protected by external free apophyses (eight tropical and four geotomical polar spines).

The genus Dorypelta, the most common of all Phractopeltida which are protected by free apophyses, exhibits a very peculiar differentiation of its twenty radial spines. There are constantly eight simple spines and twelve spines with apophyses. The eight simple spines are the four equatorial spines and four polar spines placed in the hydrotomical median plane. The four other polar spines (placed in the geotomical meridian plane) and the eight tropical spines are protected by two opposite apophyses, which are now simple, now branched or shield-shaped. A similar differentiation occurs in no other Acanthophractida.

Subgenus 1. Dorypeltarium, Haeckel.

Definition.--Free apophyses of the radial spines simple, not branched.

{857}1. Dorypelta stauroptera, n. sp.

Apophyses of the long compressed radial spines simple, conical, about as long as their distance from the shell. At the base of each spine (in the outer shell) two elliptical aspinal pores, two to three times as large as the other pores.

Dimensions.--Diameter of the outer shell 0.1, of the inner 0.044.

Habitat.--North Pacific, Station 238, surface.

2. Dorypelta gladiata, n. sp.

Apophyses of the long cylindrical radial spines simple, triangular, about half as long as their distance from the shell. At the base of each spine (in the outer shell) four crossed aspinal pores, the two opposite of which are much larger than the other two pores.

Dimensions.--Diameter of the outer shell 0.09, of the inner 0.04.

Habitat.--Central Pacific, Station 266, surface.

Subgenus 2. Dorypeltidium, Haeckel.

Definition.--Free apophyses of the radial spines branched, with free (not anastomosing) branches.

3. Dorypelta furcata, n. sp.

Apophyses of the long compressed spines simply forked, each with two simple parallel fork-branches. At the base of each spine two elliptical aspinal pores, much larger than the other roundish pores.

Dimensions.--Diameter of the outer shell 0.08, of the inner 0.04.

Habitat.--Central Pacific, Station 274, surface.

4. Dorypelta tetrodon, n. sp.

Apophyses of the long compressed spines crossed by a transverse beam, which bears four simple parallel fork-branches or spikes (perpendicular to the beam), two larger medial and two smaller lateral. At the base of each spine four crossed aspinal pores of nearly equal size, little different from the other pores.

Dimensions.--Diameter of the outer shell 0.09, of the inner 0.035.

Habitat.--South Pacific, Station 284, surface.

5. Dorypelta ramosa, n. sp.

Apophyses of the long cylindrical spines crossed by a transverse beam, which bears four to six irregularly branched spikes or fork-branches, the medial of which are larger than the lateral. At {858}the base of each spine four crossed aspinal pores, two opposite of which are much larger than the two other pores.

Dimensions.--Diameter of the outer shell 0.09, of the inner 0.04.

Habitat.--South Pacific, Station 302, surface.

Subgenus 3. Dorypeltonium, Haeckel.

Definition.--Free apophyses of the radial spines branched, and forming perforated shields by union of their anastomosing branches.

6. Dorypelta lithoptera, n. sp.

Apophyses of the long compressed radial spines with anastomosing branches; each spine bearing two free separated shields (each with two roundish aspinal pores). At the base of each spine (in the network of the outer shell) two elliptical aspinal pores, larger than the other pores.

Dimensions.--Diameter of the outer shell 0.09, of the inner 0.03.

Habitat.--North Pacific, Station 239, surface.

7. Dorypelta tessaraspis, n. sp. (Pl. 133, fig. 2).

Apophyses of the long cylindrical spines with anastomosing branches; each spine bearing a single free shield with four crossed aspinal pores of equal size (on the margin of the shield twelve to sixteen spikes). At the base of each spine (in the outer shell) four crossed aspinal pores, about as large as the other roundish pores.

Dimensions.--Diameter of the outer shell 0.11, of the inner 0.05.

Habitat.--Central Pacific, Station 263, surface.

8. Dorypelta dodecaspis, n. sp.

Apophyses of the long two-edged spines with anastomosing branches; each spine bearing a single free shield with six to eight parmal pores (four crossed aspinal pores alternating with four outer coronal pores), on the margin of each shield twelve to sixteen spikes. At the base of each spine (in the outer shell) four crossed aspinal pores, about as large as the other irregular pores.

Dimensions.--Diameter of the outer shell 0.1, of the inner 0.04.

Habitat.--North Pacific (off Japan), Station 235, surface.

Genus 370. Stauropelta,[410] Haeckel, 1881, Prodromus, p. 468.

Definition.--#Phractopeltida# with four simple equatorial spines and sixteen spines protected by external free apophyses (eight tropical and eight polar spines).

{859}The genus Stauropelta is distinguished from the other Phractopeltida by the possession of sixteen pairs of free apophyses (on the eight tropical and the eight polar spines); only the other four equatorial spines remain simple, without apophyses, and form a simple cross in the equatorial plane.

1. Stauropelta cruciata, n. sp. (Pl. 133, fig. 3).

Apophyses of the long polar and tropical spines crossed by a transverse beam, which is again crossed by two perpendicular branches parallel to the apophyses; branches with free ends, not united by concrescence. At the base of each spine (in the outer shell) two large elliptical aspinal pores, larger than the other irregular pores. Four equatorial spines simple, without apophyses, of the same size as the other sixteen spines.

Dimensions.--Diameter of the outer shell 0.12, of the inner 0.05.

Habitat.--Indian Ocean (Madagascar), Rabbe, surface.

2. Stauropelta stauropora, n. sp.

Apophyses of the long polar and tropical spines crossed by a transverse beam, which is again crossed by two perpendicular branches parallel to the apophyses; these branches are united by concrescence, and form a square shield with four crossed pores, the centre of which is pierced by the spine. At the base of each spine (in the outer shell) four crossed aspinal pores, corresponding to those of the shield, of about the same size as the other roundish pores. Four equatorial spines, simple, without apophyses, somewhat larger than the other sixteen spines.

Dimensions.--Diameter of the outer shell 0.1, of the inner 0.04.

Habitat.--Indian Ocean, Sunda-Archipelago, Singapore, Trebing, surface.

----

Suborder II. PRUNOPHRACTA.

Definition.--Shell ellipsoidal, lenticular or diploconical, with radial beams of different size.

Family XLII. #BELONASPIDA#, n. fam. (Pl. 136, figs. 6-9; Pl. 139, figs. 8, 9).

Definition.--ACANTHARIA with a simple ellipsoidal lattice-shell, composed of the branched apophyses of twenty radial spines meeting in its centre and disposed according to the Müllerian law of Icosacantha. Two opposite equatorial spines larger than the two others. Central capsule ellipsoidal, enclosed in the fenestrated shell.

The family #Belonaspida#, formerly united by me with the Dorataspida (in the Prodromus, 1881, p. 468), differs from it in the ellipsoidal form of the lattice-shell and {860}the enclosed central capsule. In the spherical Dorataspida, their ancestral family, all twenty radial spines are of equal size, whilst here in the Belonaspida two opposite spines are larger than the eighteen others. These two larger or principal spines are both equatorial spines, placed in the longitudinal or major axis of the ellipsoid, or the "hydrotomical axis" (compare above, p. 719). The two other equatorial spines are constantly smaller, and lie in the transverse or minor axis of the ellipsoid, or the "geotomical axis." The geometrical proportion of these two determining axes of the ellipsoidal shell is very variable (even in one and the same species), commonly 4 : 3 or 3 : 2, rarely 2 : 1, often only 5 : 4 or 6 : 5. All meridian planes, passing through the principal spines (or the longitudinal axis of the shell) are elliptical, and of equal size. All transverse planes, perpendicular to that axis, are circular; the largest of these circular parallel planes is the geotomical plane, which passes through the smaller equatorial spines and the spineless axis.

In the spherical Dorataspida the internal length of the radial spines (or the distance between the shell and the centre) is equal in all twenty spines. In the ellipsoidal Belonaspida this internal length is different, and commonly exhibits four different degrees; in the two principal spines it is of first rank, in the eight tropical spines of second rank, in the four (hydrotomical) polar spines of third rank, and in the six spines (four geotomical polar spines and two transverse equatorial spines) of fourth rank. These differences of the internal length become more important the more the hydrotomical axis is prolonged. Regarding all other qualities (in form, disposition, and mode of junction at the centre) the ellipsoidal Belonaspida do not differ from their ancestral group, the spherical Dorataspida (compare above, p. 802). In both families the pyramidal central bases of the twenty spines are commonly supported one upon another with their triangular neighbouring faces; but sometimes also here (particularly in Phatnaspis) the central bases are perfectly grown together. In this case also the sutures of the meeting branches of the apophyses are obliterated, whilst usually they remain open. Such forms, with spines and plates perfectly grown together, form a single piece of acanthin, and were formerly separated by me as a peculiar genus Haliommatidium (Monogr. d. Radiol., 1862, p. 419). But as I now find this concrescence to be an accidental and inconstant peculiarity of some species, it no longer seems to me to be of generic importance.

The apophyses of the twenty radial spines, the branches of which compose the ellipsoidal lattice-shell, exhibit in all Belonaspida the same appearance as in the Diporaspida (and especially the Ceriaspida) among the spherical Dorataspida. Everywhere each radial spine gives off only two opposite primary apophyses, the fork-branches of which unite together and form a plate or shield with two aspinal pores (as in Dorataspis). Commonly the shell exhibits only these forty parmal pores, the other meshes between them being sutural pores. Only in one genus, Phatnaspis (Pl. 136, {861}figs. 6-9), is this number multiplied; the two opposite primary apophyses are here crossed by numerous perpendicular lateral branches, and these are again united by secondary perpendicular ramules which are parallel to the apophyses themselves; therefore each plate here forms a rhombic shield pierced by very numerous (often more than one hundred) small quadrangular or circular pores. Only two of these numerous parmal pores are the primary aspinal pores (sometimes, as in Pl. 136, fig. 8, distinguished by their larger size); all others are secondary or coronal pores. Therefore Phatnaspis repeats the characteristic formation of Coscinaspis, from which it differs in its ellipsoidal shell.

Moreover, the four other genera of the ellipsoidal Belonaspida correspond perfectly to certain genera of the spherical Dorataspida, and may be derived from these by hypertrophy or stronger development of two opposite equatorial spines. In Thoracaspis and Belonaspis (Pl. 139, figs. 8, 9) the surface of the shell-plates is without crests and dimples (in the former without, in the latter with accessory by-spines); they thus correspond to Dorataspis and Diporaspis among the Dorataspida. In two other genera the surface of the shell-plates bears a network of elevated crests, separating funnel-shaped dimples, in Dictyaspis without, in Coleaspis with by-spines; these correspond to Ceriaspis and Hystrichaspis among the Dorataspida. The small by-spines, covering the surface, exhibit the same forms as in the Dorataspida; but they are usually smaller, and less developed in the Belonaspida.

The twenty radial spines are commonly more or less compressed or two-edged, sometimes very flat, broad, and triangular (Pl. 139, figs. 8, 9). In some species (mainly of Phatnaspis) they are very long, thin, and needle-shaped (Monogr. d. Radiol., 1862, Taf. xxii. figs. 10-12). Rarely they are cylindrical, four-edged, or prismatic. The Belonaspida testify by this and other peculiarities to their near relation to the Diporaspida and Phractacanthida and their older origin from Zygacantha.

The Central Capsule is in the Belonaspida ellipsoidal, and more or less prolonged in the hydrotomical or longitudinal axis of the shell. It is constantly smaller than the enveloping ellipsoidal shell, and separated from it by the calymma. Its structure and the shape of its nucleus are the same as in the nearly allied Dorataspida.

Synopsis of the Genera of Belonaspida.

------------------------------------------------------------------------- I. Subfamily Coleaspida. Forty parmal pores (two aspinal pores on each plate, no coronal pores). ------------------------------------------------------------------------- Plates not dimpled, without { No by-spines, 371. Thoracaspis. prominent crests. { { With by-spines, 372. Belonaspis.

Plates dimpled, with a { No by-spines, 373. Dictyaspis. network of prominent { crests, { With by-spines, 374. Coleaspis. ------------------------------------------------------------------------- II. Subfamily Phatnaspida. Eighty to two thousand or more parmal pores (two aspinal pores on each plate, surrounded by two to one hundred or more coronal pores). ------------------------------------------------------------------------- No by-spines (plates not dimpled), 375. Phatnaspis.

{862}Genus 371. Thoracaspis,[411] Haeckel, 1862, Prodromus, p. 468.

Definition.--#Belonaspida# with forty parmal pores (two on each plate), without dimples and crests, also without by-spines, therefore with smooth surface.

The genus Thoracaspis is the simplest form among the Belonaspida, and repeats in this family the nearly allied genus Dorataspis among the Dorataspida. It differs from this genus only in the characteristic prolongation of one equatorial axis, which effects an ellipsoidal transformation of the spherical central capsule and the enclosing lattice-shell.

1. Thoracaspis ellipsoides, n. sp.

Parmal pores large, elliptical, five or six times as large as the small circular sutural pores. Each plate surrounded by five or six sutural pores (a single one on each side). Spines compressed triangular, sword-like, two-edged; inner and outer half of nearly equal length.

Dimensions.--Length of the ellipsoidal shell (or major axis) 0.15, breadth (or minor axis) 0.12; length of the spines 0.07, basal breadth 0.016.

Habitat.--North Pacific, Station 253, surface.

2. Thoracaspis nephropora, n. sp.

Parmal pores large, kidney-shaped, three to four times as large as the roundish small sutural pores. Each plate surrounded by five or six sutural pores (a single one on each side). Spines in the inner longer part cylindrical, in the outer shorter part conical, not compressed.

Dimensions.--Length of the shell 0.2, breadth 0.15; length of the spines 0.06, basal breadth 0.018.

Habitat.--Central Pacific, Station 268, surface.

3. Thoracaspis circopora, n. sp.

Parmal pores circular, of the same size as the circular sutural pores. Each plate surrounded by five or six sutural pores (a single one on each side). Spines compressed, thin, linear, two-edged; outer part one and a half times as long as the inner.

Dimensions.--Length of the shell 0.17, breadth 0.13; length of the spines 0.12, basal breadth 0.003.

Habitat.--South Pacific, Station 288, surface.

4. Thoracaspis bipennis, n. sp. (Pl. 139, fig. 8).

Parmal pores elliptical, about twice as large as the circular sutural pores, which are of rather variable size. Each plate surrounded by eight to twelve sutural pores (commonly two on each side). {863}Spines compressed, triangular, gradually tapering towards both ends; outer half a little longer, and much broader than the inner.

Dimensions.--Length of the shell 0.14, breadth 0.12; length of the spines 0.08, basal breadth 0.025.

Habitat.--Central Pacific, Station 274, surface.

Genus 372. Belonaspis,[412] Haeckel, 1862, Prodromus, p. 468.

Definition.--#Belonaspida# with forty parmal pores (two on each plate), without dimples and crests, but with numerous by-spines on the surface.

The genus Belonaspis differs from its ancestral genus Thoracaspis only in the possession of numerous superficial by-spines, and bears therefore to it the same relation as Diporaspis does to Dorataspis. The two latter differ from the two former in the spherical form of the central capsule and the enclosing shell, which here becomes ellipsoidal.

1. Belonaspis pandanus, n. sp.

Parmal pores elliptical, three or four times as large as the circular sutural pores. Each plate surrounded by five or six sutural pores (a single one on each side). Spines compressed, triangular; outer part half as long as the inner, and twice as long as the numerous, simple, bristle-shaped by-spines.

Dimensions.--Length of the ellipsoidal shell (or major axis) 0.12, breadth (or minor axis) 0.1; length of the spines 0.03, basal breadth 0.02.

Habitat.--South Pacific, Station 295, surface.

2. Belonaspis furcata, n. sp.

Parmal pores elliptical, twice as broad as the circular sutural pores. Each plate surrounded by five or six sutural pores (a single one on each side). Spines compressed, linear, very thin; outer part longer than the inner. By-spines very numerous, half as long as the radius, furcate, with divergent fork-branches.

Dimensions.--Length of the shell 0.1, breadth 0.08; length of the spines 0.12, breadth 0.003.

Habitat.--Indian Ocean (Cocos Islands), Rabbe, surface.

3. Belonaspis datura, n. sp. (Pl. 139, fig. 9).

Parmal pores elliptical, three or four times as large as the circular sutural pores. Each plate surrounded by ten or twelve sutural pores (two on each side). Spines triangular, two-edged, about {864}as long as the radius of the shell; gradually tapering from its surface towards both ends. By-spines very short and numerous, simple.

Dimensions.--Length of the shell 0.13, breadth 0.11; length of the spines 0.08, basal breadth 0.025.

Habitat.--Central Pacific, Station 271, surface.

4. Belonaspis lanceolata, n. sp.

Parmal pores elliptical, six or eight times as large as the small circular sutural pores. Each plate surrounded by ten to twelve sutural pores (two on each side). Spines lanceolate, flat, in the distal part needle-shaped, about as long as the diameter of the shell. By-spines very numerous, zigzag, half as long as the shell-radius.

Dimensions.--Length of the shell 0.15 breadth 0.13; length of the spines 0.14, basal breadth 0.03; length of the by-spines 0.04.

Habitat.--North Pacific, Station 235, surface.

5. Belonaspis conifera, n. sp.

Parmal pores kidney-shaped, three or four times as large as the small circular pores. Each plate surrounded by ten to twelve sutural pores (two on each side). Spines very thick, half as long in the outer conical part as in the inner cylindrical part. By-spines very short, conical.

Dimensions.--Length of the shell 0.2, breadth 0.16; length of the spines 0.05, basal breadth 0.03.

Habitat.--Central Pacific, Station 267, surface.

6. Belonaspis multiforis, n. sp.

Parmal pores circular, of the same size as the circular sutural pores. Each plate surrounded by fifteen to eighteen sutural pores (three on each side). Spines compressed, about as long as the radius. By-spines very numerous, zigzag, half as long as the radius.

Dimensions.--Length of the shell 0.22, breadth 0.18; length of the spines 0.12, basal breadth 0.012; length of the by-spines 0.06.

Habitat.--Equatorial Atlantic, Station 347, surface.

Genus 373. Dictyaspis,[413] n. gen.

Definition.--#Belonaspida# with forty parmal pores (two on each plate), without by-spines, but with a network of prominent crests on the dimply surface.

The genus Dictyaspis repeats among the Belonaspida the characteristic structure of Ceriaspis (among the Dorataspida), by the development of prominent crests forming a {865}network with dimples on the outer surface of the shields. Either all the dimples or only a part of them are pierced by a pore. The forty aspinal pores are united in pairs in twenty larger dimples. The shell is usually very thick-walled and non-transparent.

1. Dictyaspis solidissima, Haeckel.

Dorataspis solidissima, Haeckel, 1862, Monogr. d. Radiol., p. 416, Taf. xxii. figs. 6-9.

Surface of the shell with seventy to eighty funnel-shaped dimples, each of which is perforated at the base by one or two small meshes; twenty larger dimples in the centre of the plates (each with two elliptical aspinal pores), and fifty to sixty smaller sutural dimples between them (each with a single circular pore). All pores of nearly the same size. No blind dimples. Outer conical part of the thick radial spines of the same length as the inner cylindrical part. Radius of the shell four times as large as the thickness of its wall.

Dimensions.--Length of the shell 0.12, breadth 0.1; length of the spines 0.06, basal breadth 0.012.

Habitat.--Mediterranean (Messina), surface.

2. Dictyaspis favosa, n. sp.

Surface of the shell with one hundred and seventy to one hundred and ninety deep funnel-shaped dimples, seventy to eighty of which are perforated, the others blind; among the former each of the fifty to sixty smaller contains a single sutural pore, each of the twenty larger a couple of aspinal pores. All pores of nearly the same size. Outer part of the compressed two-edged spines triangular, half as long as the inner part. Radius of the shell six times as large as the thickness of its wall. (Differs from Ceriaspis favosa, Pl. 138, fig. 6, mainly in the ellipsoidal form of the shell and the different size and form of the spines.)

Dimensions.--Length of the shell 0.16, breadth 0.13; length of the spines 0.04, basal breadth 0.025.

Habitat.--Central Pacific, Station 265, surface.

3. Dictyaspis compacta, n. sp.

Surface of the shell with one hundred and seventy to one hundred and ninety deep funnel-shaped dimples, seventy to eighty of which are perforated, the others blind; among the former each of fifty to sixty each contain a single sutural pore, twenty each a couple of aspinal pores. All dimples nearly of the same size, very deep. Outer part of the compressed sword-like spines somewhat longer than the inner part. Radius of the dark shell only twice as large as the thickness of its compact wall.

Dimensions.--Length of the shell 0.18, breadth 0.15; length of the spines 0.12, basal breadth 0.02.

Habitat.--Central Pacific, Station 274, surface.

{866}Genus 374. Coleaspis,[414] Haeckel, 1881, Prodromus, p. 468.

Definition.--#Belonaspida# with forty parmal pores (two on each plate), with numerous by-spines and with a network of prominent crests on the dimpled surface.

The genus Coleaspis differs from its ancestral genus Dictyaspis in the development of numerous by-spines, and bears therefore among the ellipsoidal Belonaspida the same relation to it as Hystrichaspis does to Coscinaspis among the spherical Dorataspida. If the four equatorial spines in Coleaspis become different in pairs, it passes over into Hexalaspis. The shell is usually very dark and thick-walled.

1. Coleaspis coronata, n. sp.

All twenty spines of nearly equal size and form, about as long as the radius of the shell, compressed, sword-like, two-edged; both equatorial spines of the hydrotomical axis little longer than the eighteen others. Crests between the dimples of the shell-surface dentated, forming around the basal half of each spine a cylindrical sheath with a dentated, crown-like mouth, the teeth of which are prolonged into simple by-spines. (Similar to Hexaconus coronatus, Pl. 139, fig. 5, but differing in the nearly equal size of the spines and their sheaths, and in the longer by-spines.)

Dimensions.--Major axis of the shell 0.2, minor 0.17; length of the spines 0.12, basal breadth 0.02.

Habitat.--Central Pacific, Station 266, surface.

2. Coleaspis vaginata, n. sp. (Pl. 140, fig. 13).

All twenty spines of nearly equal size and form, nearly as long as the diameter of the shell, conical; both equatorial spines of the hydrotomical axis about one-third longer than the eighteen others. Crests between the dimples of the shell-surface serrated, forming around the basal half of each spine a conical truncate sheath with crested surface and serrated mouth, the teeth of which are prolonged into short by-spines. (Similar to Hexaconus vaginatus, Pl. 139, fig. 7, but differing in the nearly equal size of all the spines and in the double thickness of the shell-wall.)

Dimensions.--Major axis of the shell 0.12, minor 0.1, length of the spines 0.08, basal breadth 0.01.

Habitat.--North Pacific, Station 253, surface.

3. Coleaspis obscura, n. sp.

All twenty spines of nearly equal size and form, little longer than their large cylindrical sheaths, which are nearly as long as the radius of the shell, and armed on the truncated mouth with strong triangular by-spines, both equatorial spines of the hydrotomical axis one and a half times as long as the eighteen others. Shell very dark and thick walled, quite opaque.

{867}Dimensions.--Major axis of the shell 0.1, minor 0.08; length of the spines 0.06, of their sheaths 0.04.

Habitat.--Arctic Ocean, Greenland, Koch, surface.

4. Coleaspis occulta, n. sp.

All twenty spines of nearly equal size and form, quite concealed in their long cylindrical sheaths, which are somewhat longer than the radius of the shell, and armed on the truncated mouth with acute simple teeth; each sheath deeply sulcated, apparently resulting from the concrescence of numerous parallel leaf-shaped by-spines. Small shell very dark and thick-walled, quite opaque.

Dimensions.--Major axis of the shell 0.08, minor 0.06; length of the spines and their sheaths 0.05 to 0.06.

Habitat.--Antarctic Ocean (off Kerguelen), Station 159, surface.

Subgenus 2. Coleaspidium, Haeckel.

Definition.--Both equatorial spines of the hydrotomical axis much larger and of peculiar form, different from the eighteen other spines.

5. Coleaspis amphilonche, n. sp.

Both equatorial spines of the hydrotomical axis much longer than the eighteen others, and of very different form; one and a half times as long as the diameter of the shell, prismatic, with six prominent edges, pyramidal at the distal point. The eighteen other spines triangular, compressed, two-edged, scarcely as long as the radius of the thick-walled shell. Pores of the shell irregular polygonal, separated by ciliated crests, which bear simple by-spines (one-third as long as the radius).

Dimensions.--Major axis of the shell 0.15, minor 0.12; length of the two larger spines 0.22, of the eighteen smaller 0.06 to 0.08; basal breadth of the former 0.03, of the latter 0.008.

Habitat.--South Atlantic, Station 341, surface.

6. Coleaspis hydrotomica, n. sp. (Pl. 140, fig. 14).

Both equatorial spines of the hydrotomical axis much larger than the eighteen others, and of very different form; about as long as the diameter of the shell, in the basal half four-sided pyramidal, with four thick prominent edges, in the middle part constricted, in the distal half lanceolate, two-edged. Both equatorial spines of the geotomical axis of similar form, but much smaller, scarcely one-third as long. The sixteen other spines sword-like, thin, two-edged, about as long as the radius of the thick-walled shell. Pores of the shell irregular roundish, separated by high dentated crests, which bears zigzag by-spines (half as long as the radius).

Dimensions.--Major axis of the shell 0.12, minor axis 0.1; length of the two larger spines 0.11, of the eighteen others 0.04 to 0.06; basal breadth of the former 0.04, of the latter 0.01.

Habitat.--Cape of Good Hope, Station 143, surface.

{868}Genus 375. Phatnaspis,[415] Haeckel, 1881, Prodromus, p. 468

Definition.--#Belonaspida# with eighty to two thousand or more parmal pores (four to one hundred or more on each plate), without by-spines on the surface.

The genus Phatnaspis corresponds to the spherical Coscinaspis among the Dorataspida, and differs from the other Belonaspida in the great number of the parmal pores; whilst the four other preceding genera exhibit only two opposite aspinal pores in the centre of each plate, in this there are constantly numerous coronal pores in addition to these, and the plates always possess the characteristic form of a wainscotted or panelled work, with quadrangular meshes. The number of these parmal pores amounts in each plate to from ten to twenty, often one hundred and twenty or more; therefore the number of parmal pores in the whole shell amounts to two thousand or more. Sometimes the pores are circular, but in this case too they are surrounded by quadrangular frames. The quadrangles are sometimes quite regular squares, sometimes more or less irregular. The thin and fragile bars between the quadrangular pores form in each plate two peculiar systems of parallel crests, which cross at right angles. Commonly the parallel crests of one system (parallel to the major diameter of the compressed radial spines) are equidistant, and pierce from one edge of the plate to the opposite, whilst the parallel crests of the other system (parallel to the minor diameter of the spines) are interrupted and at different distances (Pl. 136, fig. 9); but in other species both crossed systems are quite regular. In each plate there is one primary diagonal rib (often stronger than the parallel crests) which connects the two opposite corners of the rhomboidal plate. We can distinguish in this genus three different subgenera: A. in Phatnasparium the primary diagonal rib arises from both flat sides of the compressed sword-like, radial spines; B. in Phatnasplenium from both sharp edges of them; C. in Phatnaspidium two crossed diagonal ribs arise from four edges of the spines (combination of A and B). Therefore in the first subgenus (A) two primary aspinal pores are placed opposite on the sharp edges of the spines, but in the second (B) inversely on their flat sides; in the third (C) there are apparently four primary aspinal pores, which are probably derived from B or A by division of the two pores.

Subgenus 1. Phatnasparium, Haeckel.

Definition.--In the centre of each rhomboidal plate two primary aspinal pores, opposite on both edges of the compressed spines, from both flat sides of which the primary diagonal crest arises.

{869}1. Phatnaspis lacunaria, n. sp. (Pl. 136, fig. 9).

Parmal pores irregular quadrangular, of unequal size and form, ten to twelve on each side of the primary diagonal rib, which arises from both flat sides of the two-edged spines; two primary aspinal pores opposite on both edges of the latter. Spines much compressed, sword-like, their outer half shorter than the inner.

Dimensions.--Length of the shell 0.21 to 0.23, breadth 0.18 to 0.2; basal breadth of the spines 0.01.

Habitat.--Central Pacific, Station 268, surface.

2. Phatnaspis ensiformis, n. sp.

Parmal pores irregular quadrangular, of unequal size and form, six to eight on each side of the primary diagonal rib, which arises from both flat sides of the two-edged spines; two primary aspinal pores opposite on the two edges of the latter. Spines very broad, strongly compressed, sword-like, their outer half larger than the inner.

Dimensions.--Length of the shell 0.16, breadth 0.11; basal breadth of the spines 0.02.

Habitat.--Tropical Atlantic, Station 348, surface.

3. Phatnaspis loculata, n. sp.

Parmal pores regular quadrangular, of nearly equal size and form, twelve to sixteen on each side of the primary diagonal rib, which arises from both flat sides of the two-edged spines; two primary aspinal pores on the two edges of the latter. Spines linear, compressed, very long and thin, their outer half three to four times as long as the inner.

Dimensions.--Length of the shell 0.24, breadth 0.18; breadth of the spines 0.004.

Habitat.--North Atlantic, Station 354, surface.

4. Phatnaspis fenestrata, Haeckel.

Haliommatidium fenestratum, Haeckel, 1862, Monogr. d. Radiol., p. 421.

Parmal pores regular quadrangular, of nearly equal size and form, six to eight on each side of the primary diagonal rib, which arises from both flat sides of the two-edged spines; two primary aspinal pores on the two edges of the latter. Spines linear, little compressed, or nearly needle-shaped, very long and thin, their outer half five to ten times as long as the inner.

Dimensions.--Length of the shell 0.11 to 0.12, breadth 0.07 to 0.08; breadth of the spines 0.002.

Habitat.--Mediterranean (Messina), surface.

5. Phatnaspis cristata, n. sp. (Pl. 136, fig. 6).

Parmal pores circular, of very different size, separated by high square crests, ten to twelve on each side of the high, comb-like, primary diagonal rib, which arises from both flat sides of the {870}twoedged spines; two primary aspinal pores on the two edges of the latter. Each circular pore is surrounded by a square frame. Spines sword-like, strongly compressed, their outer part longer than the inner.

Dimensions.--Length of the shell 0.2 to 0.22, breadth 0.16 to 0.18; basal breadth of the spines 0.01.

Habitat.--North Pacific, Station 254, surface.

6. Phatnaspis coscinoides, n. sp.

Parmal pores circular, regular, all of nearly equal size, twelve to sixteen on each side of the primary diagonal rib, which arises from both flat sides of the two-edged spines; two primary pores on the two edges of the latter. Spines linear, little compressed, their outer part much longer than the inner.

Dimensions.--Length of the shell 0.18, breadth 0.15; breadth of the spines 0.006.

Habitat.--South Atlantic, Station 325, surface.

Subgenus 2. Phatnasplenium, Haeckel.

Definition.--In the centre of each rhomboidal plate two primary aspinal pores, opposite on the two flat sides of the compressed spines, from the two edges of which the primary diagonal crest arises.

7. Phatnaspis orthopora, n. sp.

Parmal pores irregular quadrangular, of unequal size and form, four to six on each side of the primary diagonal rib, which arises from both edges of the compressed spines; two larger primary aspinal pores opposite on the two flat sides of the latter. Spines very thin and long, linear, their outer half three to four times as long as the inner.

Dimensions.--Length of the shell 0.08, breadth 0.06; breadth of the spines 0.003.

Habitat.--North Atlantic, Station 353, surface.

8. Phatnaspis polypora, n. sp.

Parmal pores irregular polygonal, of very unequal size and form, sixteen to twenty on each side of the primary diagonal rib, which arises from both edges of the compressed spines; two very large, lanceolate, primary aspinal pores opposite on the two flat sides of the latter. Spines very thin, linear, on the outside of the shell rudimentary. (This remarkable species somewhat resembles Coscinaspis polypora, Pl. 136, fig. 8.)

Dimensions.--Length of the shell 0.32, breadth 0.24; breadth of the spines 0.002.

Habitat.--South Atlantic, Station 332, surface.

{871}9. Phatnaspis quadratura, n. sp.

Parmal pores regular, square, all of nearly equal size and form, ten to twelve on each side of the primary diagonal rib, which arises from both edges of the compressed spines; two primary aspinal pores opposite on the two flat sides of the latter, not different from the other pores. Spines sword-like, their outer part about as long as the inner.

Dimensions.--Length of the shell 0.2, breadth 0.16; basal breadth of the spines 0.004.

Habitat.--Central Pacific, Station 274, surface.

10. Phatnaspis tabulata, Haeckel.

Haliomma tabulatum, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 37, Taf. v. figs. 5-8.

Haliomma tabulatum, Haeckel, 1862, Monogr. d. Radiol., p. 429.

Parmal pores regular, circular, with square frames, all of nearly equal size, eight to ten on each side of the primary diagonal rib, which arises from both edges of the compressed spines; two primary aspinal pores opposite on the flat sides of the latter. Spines sword-like, short, scarcely half as long as the radius of the shell, their central ends are thickened and cause by their union the deceptive appearance of an enclosed "medullary shell."

Dimensions.--Length of the shell 0.12 to 0.15, breadth 0.1 to 0.12; breadth of the spines 0.006.

Habitat.--Mediterranean; Nice, Müller; Portofino, near Genoa, Haeckel, surface.

Subgenus 3. Phatnaspidium, Haeckel.

Definition.--In the centre of each rhomboidal plate four primary aspinal spines, forming a regular cross, the centre of which receives the cylindrical or four-sided prismatic spine.

11. Phatnaspis haliommidium, n. sp. (Pl. 136, fig. 7).

Parmal pores irregular quadrangular, of unequal size and form, eight to ten on each side of the crossed diagonal ribs, which arise at right angles from the four edges of the prismatic spines; four primary aspinal pores not different from the others. Outer part of the strong spines scarcely longer than the inner. (Resembling Icosaspis tabulata, Pl. 136, fig. 2, which, however, is distinguished by the spherical shell and the larger pores.)

Dimensions.--Length of the shell 0.22, breadth 0.17; breadth of the spines 0.016.

Habitat.--North Pacific, Station 244, surface.

12. Phatnaspis mülleri, n. sp.

Haliommatidium mülleri, Haeckel, 1862, Monogr. A. Radiol, p. 419, pl. xiii. figs. 10-12.

Parmal pores regular, square, all of nearly equal size and form, twelve to sixteen on each side of the crossed diagonal ribs, which arise at right angles from the needle-shaped spines; the four {872}primary aspinal pores not different from the others. Spines very thin and long, cylindrical; four to six times longer in the outer than in the inner part.

Dimensions.--Length of the shell 0.24, breadth 0.16; breadth of the spines 0.002.

Habitat.--Mediterranean (Messina), surface.

Family XLIII. #HEXALASPIDA#, n. fam. (Pl. 139).

Definition.--ACANTHARIA with a simple discoidal or lenticular lattice-shell, composed of the branched apophyses of twenty radial spines meeting in the centre and disposed according to the Müllerian law of Icosacantha. Six larger spines in the hydrotomical plane, prominent on the margin of the circular or elliptical biconvex lens. Fourteen other spines much smaller or rudimentary. Central capsule biconvex lenticular, enclosed in the fenestrated shell.

The family #Hexalaspida# represents a new small, but very interesting group of Acanthophracta, which differs from all others in the lentelliptical or triaxial form of the lenticular lattice-shell, the margin of which bears six larger spines placed in the hydrotomical plane (compare above, p. 719). They may therefore be characterised shortly as "Acanthophracta lentelliptica," with three different dimensive axes and six larger marginal spines. A closer comparison with the other ACANTHARIA leaves no doubt that the Hexalaspida must be derived from the Belonaspida by stronger development of six radial spines placed in the hydrotomical plane, namely, two equatorial and four associated polar spines; whilst the six spines of the geotomical plane (perpendicular to the former) are much smaller; the eight tropical spines are intermediate in size between the former and the latter.

The geometrical fundamental form of the Hexalaspida (of the central capsule as well as of the enclosing shell) is therefore lentelliptical, with three different dimensive axes, and they exhibit among the ACANTHARIA a relation to the spherical Dorataspida and the ellipsoidal Belonaspida similar to that which the lentelliptical #Larcoidea# exhibit to the spherical #Sphæroidea# and the ellipsoidal #Prunoidea# among the #Sphærellaria# (compare above, p. 599). The largest of the three dimensive axes (which are perpendicular to one another) is here the hydrotomical axis, the shortest, on the contrary, the geotomical axis; the intermediate in size being the spineless axis. The development of the whole body is strongest in the hydrotomical meridian plane, in which the six principal spines are placed; it is weakest in the geotomical plane, in which the six smallest spines are placed; the eight tropical spines are intermediate in size between the others. This peculiar development is illustrated by the figures of Pl. 139, where the four equatorial spines are everywhere marked by c, the eight tropical spines by b and d, the eight polar spines by a and e.

{873}Rarely the six hydrotomical or principal spines are of equal size, and thus the margin of the shell may be quite circular or regularly hexagonal (Pl. 139, figs. 1-3); the two equatorial spines of the hydrotomical plane are usually larger than its four polar spines, and thus the margin of the shell becomes more or less elliptical (Pl. 139, figs. 4-7). Usually (almost constantly) these six larger spines are more or less compressed, triangular, often very broad and flat; their two edges lie in the hydrotomical plane. Their two flat surfaces are often furrowed, with longitudinal ribs or crests converging towards the simple apex of the spines.

The fourteen smaller spines are regularly disposed according to the Müllerian law of Icosacantha on both convex sides of the lenticular shell; they are not only smaller than the six principal spines, but often also of different form, much thinner and shorter, sometimes needle-shaped. In the genera Hexonaspis and Hexacolpus (Pl. 139, figs. 1, 2) only their inner part (inside of the shell) is developed, whilst their outer part is quite rudimentary and not prominent on the surface. Therefore these genera appear to possess only six marginal spines externally.

The Lenticular Shell itself offers in the Hexalaspida great difficulties in the way of accurate study, as its wall is constantly very thick and dark, often quite opaque and non-transparent. However, prolonged accurate researches have convinced me that its structure is essentially the same as in the Belonaspida and especially in the genera Dictyaspis and Coleaspis. As in these latter the twenty plates of the shell bear high crests or combs on the outer surface, and by these funnel-shaped dimples are separated. The network of these crests is more or less regular (Pl. 139, figs. 1-7). Around the base of each radial spine the shell is usually elevated in the form of a conical or cylindrical sheath; the crests are prolonged into the sheaths as longitudinal ribs, parallel to the spine or convergent towards its apex. Whilst in Hexalaspis and Hexonaspis these basal sheaths are not at all or but little prominent (Pl. 139, fig. 2; Pl. 140, fig. 16), in Hexaconus and Hexacolpus they envelop the basal half (or even more) of the spines, and very often the circular or elliptical free distal edge of the sheath is elegantly denticulated or serrated (Pl. 139, figs. 1, 3-7; pl. 140, figs. 9-16).

The Pores of the shell exhibit in the Hexalaspida the same shape as in the majority of the Belonaspida. Each spine bears only two broad opposite apophyses, the fork-branches of which unite to form a polygonal shield with two pores. The number of parmal pores is constantly (?) forty, as each plate possesses only two primary aspinal pores; there are no secondary or coronal pores. The numerous (between fifty and one hundred, rarely more) smaller pores between the forty parmal pores are probably always sutural pores; however, their number and position is very difficult to determine, on account of the high protecting crests; the majority of the funnel-shaped dimples between the latter seem to be blind, not perforated. Sometimes all the dimples, except the twenty spinal ones, seem to be blind and the sutural pores appear {874}to have disappeared completely, so that there remain only twenty aspinal pores (Pl. 139, fig. 4).

The internal cavity of the shell in all Hexalaspida is very small, on account of the thickness of the massive wall; the latter is often greater than the diameter of the cavity. Setting aside this disproportion, the space of the cavity is further much reduced by the internal parts of the thick radial spines, which are united in the centre by their pyramidal bases (Pl. 140, fig. 15). Usually the twenty bases seem to remain free (supported one upon another by means of their triangular faces); but sometimes they seem to grow together perfectly and to form a single central star of acanthin. In some species, too, the sutures of the meeting branches of the apophyses of neighbouring spines seem to grow together, so that the whole shell exhibits a single piece of acanthin.

The Central Capsule of the Hexalaspida is therefore very small and seems to fill up the greatest part of the shell-cavity. Its form is constantly more or less lenticular, sometimes lentelliptical. On account of the opacity of the shell I could not make out its shape more closely.

Synopsis of the Genera of Hexalaspida.

All twenty spines externally } Sheaths of the spines developed, prominent on } not prominent, 376. Hexalaspis. the surface of the } lenticular shell. } Sheaths of the spines } prominent, 377. Hexaconus.

Only six spines (the } hydrotomical spines) } Sheaths of the spines externally developed and } not prominent, 378. Hexonaspis. prominent on the margin } of the disk; the other } Sheaths of the spines fourteen spines not } prominent, 379. Hexacolpus. prominent. }

Genus 376. Hexalaspis,[416] n. gen.

Definition.--#Hexalaspida# with twenty prominent radial spines, which are not surrounded by prominent sheaths; the six hydrotomical spines much larger than the fourteen others.

The genus Hexalaspis is the simplest form among the Hexalaspida, and may be derived directly from Dictyaspis among the Belonaspida, by stronger development of the six hydrotomical spines. As in the following genus Hexaconus all twenty spines are prominent externally.

Subgenus 1. Hexalasparium, Haeckel.

Definition.--Six hydrotomical spines of equal size.

{875}1. Hexalaspis heliodiscus, n. sp. (Pl. 139, fig. 2).

All six hydrotomical spines of nearly equal size (or sometimes the two equatorial a little larger than the four polar spines), isosceles triangular, compressed, smooth; about as long as the radius of the shell, and half as broad at the base. The fourteen other spines very small, also triangular and compressed, but little prominent on the two convex sides of the lenticular shell.

Dimensions.--Diameter of the shell 0.11; length of the six hydrotomical spines 0.05, basal breadth 0.03.

Habitat.--Central Pacific, Station 271 to 274, surface.

2. Hexalaspis stellata, n. sp.

All six hydrotomical spines of nearly equal size, lanceolate compressed, with two longitudinal furrows on each flat side, about as long as the diameter of the shell, and one-fourth as broad at the base. The fourteen other spines very thin, also compressed, half as long and only one-fourth as broad as the six large spines.

Dimensions.--Diameter of the shell 0.14; length of the six hydrotomical spines 0.13, basal breadth 0.035.

Habitat.--South Pacific, Station 284, surface.

Subgenus 2. Hexalaspidium, Haeckel.

Definition.--Six hydrotomical spines of unequal size, two opposite (equatorial) much larger than the four other (polar) spines.

3. Hexalaspis sexalata, n. sp.

Six hydrotomical spines of unequal size; the two equatorial spines about as long as the shell-radius and twice as long as the four polar spines, which are isosceles triangular. The fourteen other spines are only half as long and one-fourth as broad as the latter, little prominent. (Resembles Hexonaspis hastata, Pl. 140, fig. 16, which is distinguishable by the furrows on the six spines and by the total absence of the fourteen external rudimentary spines.)

Dimensions.--Diameter of the shell 0.15; length of the two equatorial spines 0.08, of the four polar spines 0.04, of the fourteen other spines 0.02.

Habitat.--North Pacific, Station 240, surface.

4. Hexalaspis hexalastrum, n. sp.

Six hydrotomical spines of unequal size; the two equatorial spines somewhat longer than the diameter of the shell and three times as long as the four polar spines, all six triangular, smooth, of the same basal breadth (equal to half the radius). The fourteen other spines very thin, conical at the base, nearly as long as the radius.

{876}Dimensions.--Diameter of the shell 0.21; length of the two equatorial spines 0.24, of the eighteen others 0.08 to 0.1; basal breadth of the six larger spines 0.05, of the fourteen others 0.01.

Habitat.--Western Tropical Pacific, Station 224, surface.

5. Hexalaspis hexaglypha, n. sp.

Six hydrotomical spines of unequal size; the two equatorial very large, six-sided prismatic, twice as long as the diameter of the shell and four times as long as the four pyramidal polar spines; each of these six spines with six deep furrows between the six prominent edges. The fourteen other spines very thin, compressed, two-edged, about as long as the radius of the shell.

Dimensions.--Diameter of the shell 0.11; length of the two equatorial spines 0.2, of the eighteen others 0.04 to 0.06; basal breadth of the six larger spines 0.03, of the fourteen others 0.01.

Habitat.--Tropical Atlantic, Station 352, surface.

Genus 377. Hexaconus,[417] n. gen.

Definition.--#Hexalaspida# with twenty prominent radial spines, which are surrounded at the base by prominent sheaths; the six hydrotomical spines much larger than the fourteen others.

The genus Hexaconus differs from the preceding Hexalaspis in the development of conical or cylindrical sheaths surrounding the basal parts of the radial spines; these sheaths are developed sometimes around all twenty spines, sometimes only around the six larger hydrotomical spines.

Subgenus 1. Hexaconarium, Haeckel.

Definition.--Six hydrotomical spines of equal size.

1. Hexaconus ciliatus, n. sp. (Pl. 139, fig. 3).

All six hydrotomical spines of nearly equal size, pyramidal, with six prominent edges, somewhat longer than the radius of the shell. Sheaths sulcated, finely ciliated at the mouth, twice as broad as long and only one-fourth as long as the spines. The fourteen smaller spines very thin, bristle-shaped, shorter than the radius of the shell.

Dimensions.--Diameter of the shell 0.16; length of the six hydrotomical spines 0.11; basal breadth 0.03.

Habitat.--Central Pacific, Station 270, surface.

{877}2. Hexaconus coronatus, n. sp. (Pl. 139, fig. 5).

All six hydrotomical spines of equal size, conical, somewhat compressed, with two prominent edges, scarcely as long as the radius of the shell. Sheaths crested, strongly dentated on the mouth, three times as broad as long and only one-sixth as long as the spines. Fourteen smaller spines about half as large as the six principal spines, of the same form, but without coronated sheaths.

Dimensions.--Diameter of the shell 0.2; length of the six hydrotomical spines 0.1; basal breadth 0.02.

Habitat.--North Pacific, Station 253, surface.

3. Hexaconus velatus, n. sp. (Pl. 139, fig. 6).

All six hydrotomical spines of equal size, conical, somewhat compressed, shorter than the radius of the shell. Sheaths very large, truncated conical, enveloping the spines almost entirely, with crested wall, only half as broad at the constricted mouth as at the base. The fourteen smaller spines about half as large as the six principal spines, of the same form, but without large sheaths.

Dimensions.--Diameter of the shell 0.12; length of the six hydrotomical spines 0.05; basal breadth 0.01.

Habitat.--North Atlantic, Station 354, surface.

Subgenus 2. Hexaconidium, Haeckel.

Definition.--Six hydrotomical spines of unequal size, two opposite (equatorial) much larger than the four other (polar) spines.

4. Hexaconus serratus, n. sp. (Pl. 139, fig. 4).

Six hydrotomical spines of unequal size, the two equatorial being as long as the radius of the shell and one and a half times as large as the four polar; all of the same form, triangular, compressed, with six prominent edges. Sheaths cylindrical, half as long as the spines, with prominent crests, and with strong serrated teeth at the distal mouth. The fourteen smaller spines scarcely one-fourth or one-sixth as large as the six principal spines, without prominent sheaths.

Dimensions.--Diameter of the shell 0.2; length of the equatorial spines 0.1, basal breadth 0.05; length and breadth of the sheaths 0.05.

Habitat.--South Pacific, Station 288, surface.

5. Hexaconus vaginatus, n. sp. (Pl. 139, fig. 7).

Six hydrotomical spines of unequal size; the two equatorial very stout, pyramidal, six-edged, nearly as long as the diameter of the shell, and on the base three to four times as broad as the eighteen other spines, which are much thinner, all nearly of equal length, and two-edged. All {878}twenty spines are provided with prominent basal sheaths, which are truncate conical, sulcate, and dentate on the narrowed distal mouth. The sheaths of the six hydrotomical spines are twice to three times as large as those of the fourteen smaller spines.

Dimensions.--Diameter of the shell 0.15; length of the spines 0.12; basal breadth of the equatorial spines 0.04, of the other spines 0.02; length of the hydrotomical sheaths 0.05, of the other sheaths 0.02.

Habitat.--Central Pacific, Station 274, surface.

6. Hexaconus echinatus, n. sp. (Pl. 140, fig. 12).

Six hydrotomical spines of unequal size; the two equatorial, and their sheaths twice as large as the four polar spines. These six spines are six-edged, pyramidal, and their basal half enveloped by very large conical sheaths which are sulcate, and twice as broad on the dentate distal mouth as on the narrower base. The other fourteen spines are very thin, two-edged, half as long, with low sheaths. Approaches some forms of Diploconus.

Dimensions.--Diameter of the shell 0.15; length of the equatorial spines 0.13, of the polar spines 0.08.

Habitat.--Indian Ocean, Belligemma, Ceylon, Haeckel, surface.

Genus 378. Hexonaspis,[418] n. gen.

Definition.--#Hexalaspida# with six prominent radial spines (in the hydrotomical plane) which are not surrounded by prominent sheaths; the fourteen other spines quite rudimentary, not prominent.

The genus Hexonaspis and the following Hexacolpus differ from the two preceding genera in the rudimentary shape of the fourteen reduced and stunted smaller spines; these are only developed inside the shell, and are not prominent outside over its surface.

Subgenus 1. Hexonasparium, Haeckel.

Definition.--Six hydrotomical spines of equal size.

1. Hexonaspis heliosestrum, n. sp.

All six hydrotomical spines of nearly equal size, isosceles triangular, compressed, smooth, about as long as the diameter of the shell and three times as long as broad at the base. This species is very similar to Hexalaspis heliodiscus (Pl. 139, fig. 2), but differs in the larger size of the six marginal spines and in the complete external absence of the fourteen smaller spines.

{879}Dimensions.--Diameter of the shell 0.13; length of the six marginal spines 0.12, basal breadth 0.04.

Habitat.--Tropical Atlantic, Station 348, surface.

2. Hexonaspis hexapleura, n. sp. (Pl. 140, fig. 15).

All six hydrotomical spines of nearly equal size, triangular, compressed, six-edged, about as long as the radius of the shell and twice as long as broad on the base. Two strong prominent ribs on each flat side of the spines. Shell very thick-walled, with a very small cavity.

Dimensions.--Diameter of the shell 0.11; length of the six marginal spines 0.06, basal breadth 0.03.

Habitat.--South Atlantic, Station 332, surface.

3. Hexonaspis hexagona, n. sp.

All six hydrotomical spines of equal size, very short, triangular, only half as long as broad at the base. The whole shell accordingly forms a regular hexagon, the six corners of which are formed by the distal points of the rudimentary spines, the six sides by their straight lateral edges. Shell very dark.

Dimensions.--Diameter of the shell 0.2; length of the six marginal spines 0.03, basal breadth 0.06.

Habitat.--South Atlantic (east of Patagonia), Station 318, surface.

Subgenus 2. Hexonaspidium, Haeckel.

Definition.--Six hydrotomical spines of unequal size, two opposite (equatorial) much larger than the four other (polar) spines.

4. Hexonaspis hastata, n. sp. (Pl. 140, fig. 16).

Six hydrotomical spines of unequal size; two larger equatorial spines with six prominent wings, about as long as the radius of the shell and half as broad at the base; the four polar spines quite as broad, but only half as long, nearly equilateral triangular, with two shallow furrows on each flat side at the broader base. The fourteen smaller spines not visible on the surface, quite rudimentary. Crests of the surface elegantly denticulated.

Dimensions.--Diameter of the shell 0.14; length of the two equatorial spines 0.08, of the four polar spines 0.04; basal breadth 0.04.

Habitat.--Central Pacific, Station 271, surface.

{880}Genus 379. Hexacolpus,[419] n. gen.

Definition.--#Hexalaspida# with six prominent radial spines (in the hydrotomical plane), which are surrounded by prominent sheaths at the base; the fourteen other spines quite rudimentary, not prominent.

The genus Hexacolpus differs from the preceding Hexonaspis in the development of conical or cylindrical sheaths around the basal parts of the radial spines. It bears to the latter the same relation as Hexaconus exhibits to Hexalaspis.

Subgenus 1. Hexacolparium, Haeckel.

Definition.--Six hydrotomical spines all nearly of equal size.

1. Hexacolpus nivalis, n. sp. (Pl. 139, fig. 1).

Hexalaspis nivalis, Haeckel, 1882, Manuscript et Atlas.

All six hydrotomical spines of nearly equal size and equidistant, thin, lanceolate, compressed, somewhat shorter than the diameter of the hexagonal shell. Sheaths nearly prismatic, conical in the distal third, each with twelve prominent parallel crests, which are separated by twelve deep furrows; their contracted distal opening or mouth denticulate. The sheaths are as long as the radius of the shell, and envelop two-thirds of the spines. (Resembles certain forms of snow-crystals.)

Dimensions.--Diameter of the shell 0.15, thickness of its wall 0.08; length of the spines 0.1, of the sheath 0.007; breadth of the latter 0.04.

Habitat.--West Tropical Pacific, Station 225, surface.

2. Hexacolpus conifer, n. sp.

All six hydrotomical spines of equal size and equidistant, triangular, compressed, about as long as the radius of the circular shell. Sheaths conical, sulcate, half as broad on the serrate distal end as on the base. The sheaths envelop the basal half of the spines.

Dimensions.--Diameter of the shell 0.18; length of the spines 0.1, of the sheaths 0.06; basal breadth of the latter 0.07, distal breadth 0.04.

Habitat.--North Pacific, Station 236, surface.

Subgenus 2. Hexacolpidium, Haeckel.

Definition.--Six hydrotomical spines of unequal size, two opposite (equatorial) much larger than the four other (polar) spines.

{881}3. Hexacolpus trypanon, n. sp. (Pl. 140, fig. 11).

Six hydrotomical spines of unequal size, two equatorial about as long as the diameter of the shell and nearly twice as large as the four polar; all of the same form, quadrangular prismatic, with prominent edges and pointed distal ends. Sheaths six-sided prismatic, with strong prominent edges and thinner parallel ribs between them; their distal mouth with six strong denticulated teeth. The sheaths envelop two-thirds of the spines, and are as broad as the radius of the shell.

Dimensions.--Diameter of the shell 0.13; length of the equatorial spines 0.12, of their sheaths 0.08; breadth of the latter 0.06.

Habitat.--South Pacific, Station 288, surface.

4. Hexacolpus dodecodus, n. sp.

Six hydrotomical spines of unequal size, two equatorial about as long as the radius of the shell and twice as large as the four polar; all of the same form, triangular, compressed, sulcated. Sheaths prismatic, with twelve prominent, parallel edges, and twelve strong serrated triangular teeth on the mouth. The sheaths envelop the basal half of the spines. This species greatly resembles Hexaconus serratus (Pl. 139, fig. 4), but differs in the larger size of the equatorial spines and the complete reduction of the fourteen smaller spines.

Dimensions.--Diameter of the shell 0.2; length of the equatorial spines 0.1, of their sheaths 0.06; breadth of the latter 0.08.

Habitat.--North Pacific, Station 248, surface.

5. Hexacolpus infundibulum, n. sp. (Pl. 140, fig. 10).

Six hydrotomical spines of unequal size, two equatorial about twice as long as the diameter of the shell and as the four polar spines; all six spines of the same form, quadrangular prismatic, pointed at the distal pyramidal end. Sheaths conical, two to three times as broad at the denticulate distal mouth as at the narrow base, sulcate; the mantle of the cone concavely vaulted. The large sheaths envelop two-thirds or three-fourths of the spines.

Dimensions.--Diameter of the shell 0.1 to 0.13; length of the equatorial spines 0.15 to 0.2, of their sheaths 0.1 to 0.15; basal breadth of the latter 0.04, distal breadth 0.12.

Habitat.--Central Pacific, Station 272, surface.

Family XLIV. #DIPLOCONIDA#, Haeckel (Pl. 140).

Diploconida, Haeckel, 1862, Monogr. d. Radiol., p.404.

Definition.--ACANTHARIA with simple diploconical shell, composed of two very large equatorial spines which are opposite in the hydrotomical axis, are surrounded by conical or cylindrical, often compressed sheaths, and arise from a small central {882}lattice-shell. Eighteen other spines (disposed according to the Müllerian law of Icosacantha) much smaller, often rudimentary. Central capsule ellipsoidal or diploconical.

The family #Diploconida#, founded by me in 1862 for a single Mediterranean species (Diploconus fasces), appears to be the most aberrant and strange form among the ACANTHARIA. As I had met with only a single specimen, very dark and intransparent in its central part, my observations on its structure were imperfect and the explanation of it partly erroneous (compare my Monograph, pp. 46, 404, Taf. xx. figs. 7, 8). However, I regarded Diploconus as the representative of quite a peculiar family, derived from the Acanthometrida, and I correctly compared the large opposite radial spines of one equatorial axis with the corresponding parts in Amphilonche.

Afterwards Richard Hertwig observed some specimens of Diploconus fasces in the same locality (Messina), and gave an accurate description of its central capsule, including numerous small nuclei (1879, Organismus d. Radiol., p. 28, Taf. ii. fig. 3). He found also that the peculiar diploconical skeleton is not composed of silex, but of acanthin. In the explanation of the shell-structure he adopted my opinion.

In the rich collections of the Challenger I detected ten different forms of Diploconida, all very rare, and for the most part represented only by single specimens. A twelfth species was found by me in the collection of Captain Rabbe from the Indian Ocean. By the study of these new forms, and particularly by their comparison with the most nearly allied Hexalaspida and Belonaspida, it was possible for me to correct some errors in my former description and to give a much more correct description and natural explanation of this very peculiar and strange family of Radiolaria (compare Pl. 140).

The most characteristic and the most voluminous part of the acanthinic skeleton in all Diploconida appears as the diploconical or nearly cylindrical solid "mantle" giving them their name and odd appearance (Pl. 140). Usually this mantle is broader on its two opposite terminal openings than in its more or less constricted middle part. This latter is now more spherical or ellipsoidal, now more lenticular, and usually separated from the two cones by two slight transverse strictures. On the surface of this middle part twelve to eighteen radial spines, which in Diplocolpus are rudimentary or absent, are visible in Diploconus. The longitudinal axis of this shell is constantly occupied by a very large pair of opposite stout prismatic or cylindrical principal spines, which are united in the centre and usually more or less prominent with their distal apex over the two openings of the double cone.

In my first communication on the Diploconus (1862, loc. cit.) I correctly compared these two large spines in the prolonged main axis of the shell to the principal equatorial spines of Amphilonche (or to the "hydrotomical spines," _c_1, _c_3); but my explanation of the two peculiar cones enveloping them was erroneous. I supposed at that time that they were formed by the eight flattened and leaf-shaped curved {883}tropical spines, so that around each principal spine the four neighbouring tropical spines (two of the northern and two of the southern hemisphere) had grow together by their edges and formed the peculiar conical sheath. I can now say that this opinion (afterwards adopted also by Hertwig) was quite erroneous, the two conical or funnel-shaped sheaths being the enlarged basal sheaths of the two hydrotomical spines, which we have already seen in the Hexalaspida (Pl. 139). But whilst in these latter all six principal spines of the hydrotomical meridian plane are hypertrophied (two equatorial and four polar spines), in the nearly allied Diploconida only the two opposite equatorial spines are developed, whilst all other eighteen spines are more or less atrophied or quite rudimentary. In Diploconus the latter are more or less evident, whilst in Diplocolpus they disappear externally.

The true lattice-shell of the #Acanthophracta# (constantly composed of the meeting apophyses of twenty radial spines) is therefore represented in the Diploconida by the small roundish middle part of the whole shell, which is usually much smaller than the two opposite cones, and separated from them by the two slight transverse strictures. Usually this small but most important middle part of the shell is very dark and opaque, on account of its very thick wall and small pores; but in some species it is clear enough to ascertain that the structure of this lattice-shell is the same as in the lenticular Hexalaspida, there being a network of thick crests on the outer surface and small pores in the dimples between them. Indeed, in many (and probably in all) Diploconida the forty aspinal pores are present which we found in all Hexalaspida, Belonaspida, and Diporaspida, so that these four families of #Acanthophracta# represent one continuous phylogenetical series; Phractaspis among the Diporaspida is at the beginning, and Diplocolpus among the Diploconida at the end of this remarkably transformed morphological series.

The twenty radial spines in all Diploconida are probably united very firmly (or even perfectly grown together) in the centre of the small thick-walled lattice-shell, the inner space of which is extremely reduced. Probably, too, the sutures between the meeting apophyses of the thick radial spines are often (or even constantly) obliterated by concrescence, so that the whole shell forms a single piece of acanthin. But I regret that I cannot ascertain these and other points in the structure of the shell, as the small number of specimens observed did not permit an anatomical examination to be made. I have no doubt, however, that the structure of the whole of the middle main part of the shell is quite the same as in the lenticular shell of the thick-walled Hexalaspida, and that in both families each of the twenty radial spines bears originally only two opposite apophyses.

The characteristic mantle of the double cone of the Diploconida, or the basal sheath of their two large, perfectly developed principal spines is usually much larger than the shell itself, and more or less compressed from both poles of the shortened geotomical axis. Therefore the transverse section of the two cones is usually elliptical, more {884}rarely circular. Their widest part is generally the distal opening; more rarely this is a little constricted. The thin transparent lamella of acanthin, representing the mantle of the double cone, is commonly ribbed or furrowed by longitudinal, parallel or divergent crests, and elegantly denticulated on the edge of the distal opening.

The two conical or cylindrical halves of the mantle are connected with the two enclosed principal spines not only at the base, where they arise from the small central lattice-shell, but also throughout a certain part of their length, by means of two, four, or six wings or leaves, which lie opposite and in pairs in the meridian planes of those spines. These meridian wings are more or less triangular (with broader concave outer bases), and connected by their axial edge with the spine and by their peripheral edge with the mantle. They separate two, four, or six conical spaces or pyramidal compartments in each cone. But these aspinal compartments and the separating septa are not new productions of the Diploconida, but are inherited from their ancestral family, the Hexalaspida (compare above, p. 873).

The eighteen smaller spines in Diploconus are either of nearly equal size or more or less differentiated. The eight tropical spines are often much larger than the eight polar spines. The two geotomical spines, (or the two opposite equatorial spines of the shortened geotomical axis) are often quite rudimentary. In Diplocolpus the external part (outside the shell) is in all eighteen smaller spines rudimentary or atrophied.

The Central Capsule, as shown by Hertwig, contains numerous small nuclei, and is divided into three parts by the above named two transverse strictures; the smaller central part (in the original lenticular lattice-shell) and the two opposite larger parts, filling up the greater part of the two conical or cylindrical sheaths, and more or less adopting their form. Corresponding to the shell itself the enclosed capsule is often more or less flattened, being compressed at both poles of the geotomical axis. The pseudopodia seem to proceed only from the two large polar apertures of the sheaths, and form therefore two opposite conical tufts or bunches.

Synopsis of the Genera of Diploconida.

All twenty spines more or less developed (sometimes eight of them rudimentary), 380. Diploconus.

Only the two hydrotomical spines developed (all the eighteen others rudimentary), 381. Diplocolpus.

Genus 380. Diploconus,[420] Haeckel, 1862, Monogr. d. Radiol., p. 404.

Definition.--#Diploconida# with two very large spines (opposite in the hydrotomical axis) and ten to eighteen other much smaller spines externally visible.

{885}The genus Diploconus must be derived from Hexacolpus (among the Hexalaspida) by the stronger development of the two hydrotomical spines and their large sheaths; all the other eighteen spines are much smaller, and usually devoid of prominent sheaths. Sometimes the eight tropical spines are rudimentary.

Subgenus 1. Diploconulus, Haeckel.

Definition.--Mantle of the double cone not compressed; its transverse section therefore circular.

1. Diploconus amalla, n. sp. (Pl. 140, fig. 1).

Mantle of the double cone thick walled, not compressed, its transverse section circular; its contour little convex; its surface nearly smooth; its distal margin regularly denticulated. Diameter of its mouth twice as large as the equatorial diameter of the shell and one-third as long as its total length. The two large spines prismatic, one-fourth longer than their conical sheath. The eighteen smaller spines very thin, about half as long as the former, a little curved.

Dimensions.--Length of the shell 0.3; equatorial breadth 0.05, polar breadth 0.1.

Habitat.--Central Pacific, station 271, surface.

2. Diploconus cyathiscus, n. sp. (Pl. 140, fig. 3).

Mantle of the double cone thin walled, not compressed; its transverse section circular; its contour strongly convex; its surface with six stronger and many smaller ribs; its margin with numerous straight and long, parallel denticles. Diameter of its mouth half as long as the whole shell and one and a half times as long as its equatorial diameter. The two principal spines one-fourth longer than their conical sheath. The eighteen smaller spines about half as long, thin, straight. Both geotomical spines thick and short.

Dimensions.--Length of the shell 0.2; equatorial breadth 0.07, polar breadth 0.1.

Habitat.--West Tropical Pacific, Station 225, surface.

3. Diploconus cylindrus, n. sp.

Mantle of the double cone thick walled, dark, cylindrical, not compressed; its transverse section circular; its contours straight, parallel; its surface with strong parallel straight longitudinal ribs; its margin irregularly dentated. Diameter of its mouth one-fifth as long as the whole shell and two-thirds as long as the diameter of the equatorial intumescence. The two principal spines prismatic, nearly twice as long as their cylindrical sheath. The smaller spines about half as long, thin, conical, straight. (Resembles the medial part of Hexacolpus trypanon, Pl. 140, fig. 11.)

Dimensions.--Length of the shell 0.25; equatorial breadth 0.08, polar breadth 0.05.

Habitat.--North Pacific, Station 241, surface.

{886}Subgenus 2. Diploconium, Haeckel.

Definition.--Mantle of the double cone compressed from both poles of the shortened geotomical axis; its transverse section therefore elliptical.

4. Diploconus fasces, Haeckel.

Diploconus fasces, Haeckel, 1862, Monogr. d. Radiol., p. 405, Taf. xx. figs. 7, 8.

Diploconus fasces, R. Hertwig, 1879, Organismus d. Radiol., p. 28, Taf. ii. fig. 3.

Mantle of the double cone compressed, with elliptical transverse section; its contour straight; its surface with numerous longitudinal furrows; its margin finely denticulated. Diameter of its mouth two-fifths as long as the whole shell and three times as broad as its equatorial diameter. The two main spines one-third longer than their conical sheath, four-edged. The eighteen smaller spines thick and short, cylindrical or a little compressed.

Dimensions.--Length of the shell 0.18; equatorial breadth 0.025, polar breadth 0.07.

Habitat.--Mediterranean (Messina), surface.

5. Diploconus cotyliscus, n. sp. (Pl. 140, fig. 4).

Mantle of the double cone compressed, thin walled, with elliptical transverse section; its contour convex; surface and margin nearly smooth. Diameter of its mouth half as long as the whole shell and twice as long as its equatorial diameter. The two main spines scarcely longer than their hemispherical sheath. The smaller spines conical, straight, nearly of the same length.

Dimensions.--Length of the shell 0.3; equatorial breadth 0.08, polar breadth 0.15.

Habitat.--Tropical Atlantic, Station 347, surface,

6. Diploconus saturnus, Haeckel.

Diploconus saturnus, Haeckel, 1879, Natürl. Schöpfungsgesch., Aufl. vii. p. 706, Taf. xvi. fig. 11.

Mantle of the double cone compressed, thick walled, with elliptical transverse section; its contour convex; its surface with numerous deep and irregular longitudinal furrows and marginal incisions. Diameter of its mouth one-third as long as the whole shell and twice as broad as its equatorial diameter. The two hydrotomical spines short, scarcely longer than their sheath. The eighteen other spines thin, cylindrical, nearly of the same length, curved. (Resembles a sheaf.)

Dimensions.--Length of the shell 0.24; equatorial breadth 0.04, polar breadth 0.07.

Habitat.--South Pacific, Station 300, surface.

7. Diploconus hexaphyllus, n. sp. (Pl. 140, fig. 2).

Mantle of the double cone compressed, thick walled, with elliptical transverse section; its contour straight; surface with six stronger and numerous smaller straight ribs and six marginal {887}denticulate incisions. Diameter of its mouth one-third as long as the whole shell and somewhat smaller than the equatorial diameter. Hydrotomical spines about twice as long as their sheath, pyramidal, with emarginate point and six wings. Geotomical spines short and strong, pyramidal. Sixteen other spines thin, straight, conical.

Dimensions.--Length of the shell 0.3; equatorial breadth 0.11, polar breadth 0.1.

Habitat.--Central Pacific, Station 266, surface.

Genus 381. Diplocolpus,[421] n. gen.

Definition.--#Diploconida# with only two developed, very large spines (opposite in the hydrotomical axis); all the other eighteen spines quite rudimentary or externally atrophied.

The genus Diplocolpus is the last and the most modified genus among the ACANTHARIA. The eighteen smaller spines of Diploconus are here quite rudimentary or have even perfectly disappeared by atrophy, so that the shell seems to consist only of the large hydrotomical spines and their enveloping sheaths.

Subgenus 1. Diplocolpulus, Haeckel.

Definition.--Mantle of the double cone not compressed; its transverse section therefore circular.

1. Diplocolpus costatus, n. sp. (Pl. 140, fig. 7).

Mantle of the double cone thin walled, not compressed; its transverse section circular or nearly hexagonal; its contour little convex; surface with six thick longitudinal equidistant ribs and many thinner ribs between them; margin denticulate. Transverse diameter of the shell one-third as long as the longitudinal. The two hydrotomical spines thick and short, little prominent over the polar mouth. No rudiments of other spines visible externally.

Dimensions.--Length of the shell 0.15; equatorial and polar breadth 0.05.

Habitat.--Indian Ocean (Madagascar), Rabbe, surface.

2. Diplocolpus cristatus, n. sp. (Pl. 140, fig. 6).

Mantle of the double cone thick walled, not compressed; its transverse section circular or hexagonal; its contour nearly straight; surface with six thick prominent longitudinal equidistant ribs; margin irregularly dentated. Transverse diameter of the shell half as long as the longitudinal. {888}The two hydrotomical spines very thick and short, pyramidal, little prominent. Short rudiments of the eighteen other spines present, bristle-shaped.

Dimensions.--Length of the shell 0.1, breadth 0.05.

Habitat.--South Atlantic, Station 335, surface.

Subgenus 2. Diplocolpium, Haeckel.

Definition.--Mantle of the double cone compressed from both poles of the shortened geotomical axis; its transverse section therefore elliptical.

3. Diplocolpus serratus, n. sp. (Pl. 140, fig. 5).

Mantle of the double cone thick walled, compressed, with elliptical transverse section; its surface with numerous delicate ribs; contour little convex; margin regularly serrate. Hydrotomical spines short, pyramidal, with six serrate wings. Transverse diameter of the shell nearly twice as great at the polar mouth as at the equator and half as long as the whole shell.

Dimensions.--Length of the shell 0.15; breadth on the equator 0.035, on the poles 0.07.

Habitat.--Central Pacific, Station 274, surface.

4. Diplocolpus dentatus, n. sp. (Pl. 140, fig. 9).

Mantle of the double cone thin walled, compressed, with elliptical transverse section; its contour straight; surface with six deeper and numerous shallower furrows; margin denticulated, with six triangular prominent larger teeth. Hydrotomical spines very large prismatic, pyramidal at the ends. Transverse diameter of the shell a little larger at the polar mouth than at the equator and half as long as the whole shell.

Dimensions.--Length of the shell 0.2; breadth on the equator 0.08, on the poles 0.1.

Habitat.--North Pacific, Station 244, surface.

5. Diplocolpus sulcatus, n. sp. (Pl. 140, fig. 8).

Mantle of the double cone thin walled, compressed, with elliptical transverse section; its contour straight; surface with twelve to sixteen deep longitudinal furrows, which are separated by thin, undulating, double edged ribs; margin little dentated. Hydrotomical spines short, pyramidal, with six dentate wings. Transverse diameter of the shell a little larger at the polar mouth than at the equator, about one-third of the whole length of the shell.

Dimensions.--Length of the shell 0.17; breadth on the equator 0.05, on the poles 0.06.

Habitat.--South Pacific, Station 291, surface.

Notes.

[1] The numbers preceded by L. N. refer to the list of names of authors in the Bibliography on p. clxxvi.

[2] Sitzungsb. med.-nat. Gesellsch. Jena, February 16, 1883.

[3] Loc. cit.

[4] Abhandl. d. k. Akad. d. Wiss. Berlin, 1858, p. 28.

[5] Monogr. d. Radiol., 1862, Taf. ii. p. 253.

[6] Histologie der Radiolarien, pp. 43-73, Taf. iii.-v.

[7] Sitzungsb. med.-nat. Gesellsch. Jena, February 16, 1883.

[8] Actissa = Radiant, [Greek: aktis].

[9] Thalassolampe = Sea-scum; [Greek: thalassa] and [Greek: lampê].

[10] Thalassopila = Sea-ball; [Greek: thalassa], [Greek: pila].

[11] Thalassicolla = Sea-jelly, [Greek: thalassa], [Greek: kolla].

[12] Thalassophysa = Sea-bladder; [Greek: thalassa], [Greek: physa.]

[13] Collozoum = Jelly-animal; [Greek: kolla], [Greek: zôon].

[14] Thalassosphæra = Sea-sphere; [Greek: thalassa], [Greek: sphaira].

[15] Atlantic, vol. i. p. 233, fig. 51, 1877.

[16] Thalassoxanthium = Sea-burdock; [Greek: thalassa], [Greek: xanthion.]

[17] Physematium = Small vesicle; [Greek: Physêmation].

[18] Thalassoplancta = Floating on the sea; [Greek: thalassoplankta].

[19] Compare Thalassoplancta cavispicula, Monogr. d. Radiol., 1862, p. 261, Taf. iii. figs. 10-13.

[20] Lampoxanthium = Scum-burdock; [Greek: lampe], [Greek: xanthion].

[21] Loc. cit., Taf. xxxii., xxxiii.

[22] Belonozoum = Needle-animal; [Greek: belonê], [Greek: zôon].

[23] Sphærozoum = Spherical animal; [Greek: sphaira], [Greek: zôon].

[24] Rhaphidozoum = Needle-animal; [Greek: rhaphis], [Greek: zôon].

[25] Ethmosphærida = Liosphærida simplicia = Monosphærida anacantha.

[26] Cenosphæra = Hollow sphere; [Greek: kenos], [Greek: sphaira].

[27] Stigmosphæra = Sphere with central point; [Greek: stigma], [Greek: sphaira].

[28] Ethmosphæra = Sieve-sphere; [Greek: êthmos], [Greek: sphaira].

[29] Sethosphæra = Sieve-sphere; [Greek: sêthos], [Greek: sphaira].

[30] Carposphærida = Liosphærida duplicia = Dyosphærida anacantha.

[31] Carposphæra = Fruit-shaped sphere, [Greek: karpos], [Greek: sphaira].

[32] Liosphæra = Smooth sphere; [Greek: leios], [Greek: sphaira].

[33] Thecosphærida = Liosphærida triplicia = Triosphærida anacantha.

[34] Thecosphæra = Capsule-sphere; [Greek: thêkê], [Greek: sphaira].

[35] Rhodosphæra = Rose-sphere; [Greek: rhodon], [Greek: sphaira].

[36] Cromyosphærida = Liosphærida tetraplicia = Tetrasphærida anacantha.

[37] Cromyosphæra = Onion-sphere; [Greek: chromyon], [Greek: sphaira].

[38] Caryosphærida = Liosphærida multiplicia = Polysphærida anacantha.

[39] Caryosphæra = Nut-sphere; [Greek: karyon], [Greek: sphaira].

[40] Plegmosphærida = Liosphærida spongiosa = Spongosphærida anacantha.

[41] Styptosphæra = Hemp-sphere; [Greek: styptos], [Greek: sphaira].

[42] Plegmosphæra = Sphere of wicker-work; [Greek: plegma], [Greek: sphaira].

[43] Spongoplegma = Spongy wickerwork; [Greek: spongos], [Greek: plegma].

[44] Spongodictyon = Spongy network; [Greek: spongos], [Greek: diktyon].

[45] Loc. cit., pp. 17, 55, 1858.

[46] Abhandl. d. k. Akad. d. Wiss. Berlin, p. 55, 1858.

[47] Loc. cit., p. 530, 1862.

[48] Loc. cit., pp. 30, 133, 1879.

[49] Loc. cit., p. 471, 1881.

[50] Loc. cit., p. 535, Taf. xxxiv. fig. 1.

[51] Collosphæra = Jelly-sphere; [Greek: kolla], [Greek: sphaira].

[52] Tribonosphæra = Cloak-sphere; [Greek: tribôn], [Greek: sphaira].

[53] Pharyngosphæra = Throat-sphere; [Greek: pharynx], [Greek: sphaira].

[54] Buccinosphæra = Trumpet-sphere; [Greek: bykanê], [Greek: sphaira].

[55] Acrosphæra = Pointed-sphere; [Greek: akros], [Greek: sphaira].

[56] Odontosphæra = Teeth-sphere; [Greek: odous], [Greek: sphaira].

[57] Choenicosphæra = Shell with coronel trepans; [Greek: choinikê], [Greek: sphaira].

[58] Siphonosphæra = Sphere with tubes; [Greek: siphôn], [Greek: sphaira].

[59] Mazosphæra = Teat-sphere; [Greek: mazos], [Greek: sphaira].

[60] Trypanosphæra = Auger-sphere; [Greek: trypanon], [Greek: sphaira].

[61] Caminosphæra = Chimney-sphere; [Greek: kaminos], [Greek: sphaira].

[62] Solenosphæra = Sphere with tubules; [Greek: sôlên], [Greek: sphaira].

[63] Otosphæra = Shell with ears; [Greek: otosphaira].

[64] Coronosphæra = Coronal-sphere; [Greek: koronê], [Greek: sphaira].

[65] Clathrosphæra = Lattice-sphere.

[66] Xanthiosphæra = Burdock-sphere; [Greek: xanthion], [Greek: sphaira].

[67] Stylosphærida = Sphæroidea dissacantha, Prodromus, p. 449.

[68] Xiphosphæra = Sword-sphere; [Greek: xiphos], [Greek: sphaira].

[69] Xiphostylus = Sword style; [Greek: xiphos], [Greek: stylos].

[70] Saturnalis = Similar to Saturnus, with a ring.

[71] Stylosphæra = Sphere with styles; [Greek: stylos], [Greek: sphaira].

[72] Sphærostylus = Sphere with styles; [Greek: sphaira], [Greek: stylos].

[73] Saturnulus = Small Saturnus, with a ring.

[74] Amphisphæra = Sphere with spines on both poles; [Greek: amphi], [Greek: sphaira].

[75] Amphistylus = Shell with styles on both poles; [Greek: amphi], [Greek: stylos].

[76] Saturninus = Similar to Saturnus, with a ring.

[77] Stylocromyum = Onion with styles; [Greek: stylos], [Greek: kromyon].

[78] Cromyostylus = Onion with styles; [Greek: kromyon], [Greek: stylos].

[79] Spongolonchis = Spongy shell with spears; [Greek: spongos], [Greek: lonchis].

[80] Spongostylus = Spongy shell with styles; [Greek: spongos], [Greek: stylos].

[81] Spongostylidium, diminutive of Spongostylus.

[82] Staurostylida = Staurosphærida simplicia = Monosphærida tetracantha.

[83] Staurosphæra = Cross-sphere; [Greek: stauros], [Greek: sphaira].

[84] Staurostylus = Cross-style; [Greek: stauros], [Greek: stylos].

[85] Stylostaurus, Style-cross; [Greek: stylos], [Greek: stauros].

[86] Staurolonchida = Staurosphærida duplicia = Dyosphærida tetracantha.

[87] Staurolonche = Crossed spear; [Greek: stauros], [Greek: lonchê].

[88] Staurancistra = Crossed fish-hook; [Greek: stauros], [Greek: ankistra].

[89] Staurolonchidium = Diminutive from Staurolonche.

[90] Stauroxiphos = Sword with cross; [Greek: stauros], [Greek: xiphos].

[91] Stauracontida = Staurosphærida triplicia = Triosphærida tetracantha.

[92] Stauracontium = Crossed dart; [Greek: stauros], [Greek: akontion].

[93] Staurocromyida = Staurosphærida quadruplicia = Tetrasphærida tetracantha.

[94] Staurocromyum = Cross-onion; [Greek: stauros], [Greek: kromyon].

[95] Cromyostaurus = Onion-cross; [Greek: kromyon], [Greek: stauros].

[96] Staurocaryida = Staurosphærida multiplicia = Polysphærida tetracantha.

[97] Staurocaryum = Cross-nut; [Greek: stauros], [Greek: karyon].

[98] Staurodorida = Staurosphærida spongiosa = Spongosphærida tetracantha.

[99] Staurodoras = Crossed spear; [Greek: stauros], [Greek: doras].

[100] Hexastylida = Cubosphærida simplicia = Monosphærida hexacantha.

[101] Hexastylus = Shell with six styles; [Greek: hexa], [Greek: stylos].

[102] Hexastylarium = Shell with six styles; derivation from Hexastylus.

[103] Hexastylidium = Shell with six styles; derivation from Hexastylus.

[104] Hexalonchida = Cubosphærida duplicia = Dyosphærida hexacantha.

[105] Hexalonche = Shell with six spears; [Greek: hexalonchê].

[106] Hexancistra = Shell with six fish-hooks; [Greek: hexankistra].

[107] Hexaloncharium = Shell with six spears; derivation from Hexalonche.

[108] Hexalonchidium = Shell with six spears; derivation from Hexalonche.

[109] Hexacontida = Cubosphærida triplicia = Triosphærida hexacantha.

[110] Hexacontion = Shell with six darts; [Greek: hexakontion].

[111] Hexadendron = Shell with six trees; [Greek: hexadendron].

[112] Hexacontarium = Shell with six darts; derivation, from Hexacontion.

[113] Hexacromyida = Cubosphærida quadruplicia = Tetrasphærida hexacantha.

[114] Hexacromyum = Onion with six rays; [Greek: hexa], [Greek: kromyon].

[115] Hexacaryida = Cubosphærida multiplicia = Polysphærida hexacantha.

[116] Cubosphæra = Sphere with three axes of a cubus; [Greek: kubos], [Greek: sphaira].

[117] Hexacaryum = Nut with six spines; [Greek: hexa], [Greek: karyon].

[118] Hexadorida = Cubosphærida spongiosa = Spongosphærida hexacantha.

[119] Cubaxonium = Shell with three axes like those of a cube; [Greek: kubos], [Greek: axônion].

[120] Hexadoras = Shell with six spears; [Greek: hexadoras].

[121] Hexadoridium = Shell with six small spears; derivation from Hexadoras.

[122] Acanthosphæra = Spiny sphere; [Greek: akantha], [Greek: sphaira].

[123] Heliosphæra = Sun sphere; [Greek: hêlios], [Greek: sphaira].

[124] Conosphæra = Sphere with cones; [Greek: kônos], [Greek: sphaira].

[125] Coscinomma = Sieve eye; [Greek: koskinon], [Greek: omma].

[126] Cladococcus = Nucleus with branches; [Greek: klados], [Greek: kokkos].

[127] Elaphococcus = Shell with harts' horn-shaped spines; [Greek: elaphos], [Greek: kokkos].

[128] Haliommida = Astrosphærida duplicia = Dyosphærida polycantha.

[129] Haliomma = Sea-eye; [Greek: hals], [Greek: omma].

[130] Heliosoma = Sun-body; [Greek: hêlios], [Greek: sôma].

[131] Elatomma = Pine-eye; [Greek: elatê], [Greek: omma].

[132] Leptosphæra = Delicate sphere; [Greek: leptos], [Greek: sphaira].

[133] Diplosphæra = Double sphere; [Greek: diploos], [Greek: sphaira].

[134] Drymosphæra = Woody sphere; [Greek: drymos], [Greek: sphaira].

[135] Astrosphæra = Star-sphere; [Greek: astron], [Greek: sphaira].

[136] Actinommida = Astrosphærida triplicia = Triosphærida polyacantha.

[137] Actinomma = Radiant eye; [Greek: aktis], [Greek: omma].

[138] Echinomma = Urchin-eye; [Greek: echinos], [Greek: omma].

[139] Pityomma = Pine-eye; [Greek: pitys], [Greek: omma].

[140] Cromyommida = Astrosphærida quadruplicia = Tetrasphæria polyacantha.

[141] Cromyomma = Onion-eye; [Greek: kromyon], [Greek: omma].

[142] Cromyechinus = Onion-shaped Urchin; [Greek: kromyon], [Greek: echinos].

[143] Cromyodrymus = Onion with trees; [Greek: kromyon], [Greek: drymos].

[144] Caryommida = Astrosphærida multiplica = Polysphæria polyacantha.

[145] Caryomma = Nut-eye; [Greek: karyon], [Greek: omma].

[146] Arachnopila = Cobweb ball; [Greek: arachnê], [Greek: pilos].

[147] Arachnopegma = Cobweb-building; [Greek: arachnê], [Greek: pêgma].

[148] Arachnosphæra = Cobweb-sphere; [Greek: arachnê], [Greek: sphaira].

[149] Spongiommida = Astrosphærida spongiosa = Spongosphærida polyacantha.

[150] Spongiomma = Spongy-eye; [Greek: spongia], [Greek: omma].

[151] Spongodrymus = Spongy wood; [Greek: spongos], [Greek: drymos].

[152] Spongechinus = Spongy Urchin; [Greek: spongos], [Greek: echinos].

[153] Spongothamnus = Spongy shrub; [Greek: spongos], [Greek: thamnos].

[154] Spongopila = Spongy ball; [Greek: spongos], [Greek: pilos].

[155] Rhizoplegma = Root-shaped wicker-work; [Greek: rhiza], [Greek: plegma].

[156] Lychnosphæra = Lantern-sphere; [Greek: lychnos], [Greek: sphaira].

[157] Centrocubus = Shell with a central cube; [Greek: kentron], [Greek: kubos].

[158] Octodendron = Shell with eight trees; [Greek: oktô], [Greek: dendron].

[159] Spongosphæra = Spongy sphere; [Greek: spongos], [Greek: sphaira].

[160] Rhizosphæra = Root-sphere; [Greek: rhiza], [Greek: sphaira].

[161] Cenellipsis = Hollow ellipsoid; [Greek: kenos], [Greek: elleipsis].

[162] Axellipsis = Ellipsoid with an axial beam; [Greek: axis], [Greek: elleipsis].

[163] Ellipsidium = Small ellipsoid; [Greek: elleipsidion].

[164] Ellipsoxiphus = Ellipsoid with swords; [Greek: elleipsis], [Greek: xiphos].

[165] Axoprunum = Plum with axis; [Greek: axis], [Greek: prounon].

[166] Ellipsostylus = Ellipsoid with styles; [Greek: elleipsis], [Greek: stylos].

[167] Lithomespilus = Siliceous medlar; [Greek: lithos], [Greek: mespilos].

[168] Lithapium = Siliceous pear; [Greek: lithos], [Greek: apion].

[169] Pipettella = Small pipette.

[170] Druppula = Small drupe or [Greek: druppa], ripe Olive.

[171] Druppocarpus = Olive-fruit; [Greek: druppa], [Greek: karpos].

[172] Prunulum = Little-plum.

[173] Prunocarpus = Plum fruit; [Greek: prounon], [Greek: karpos].

[174] Cromyodruppa = Onion-olive; [Greek: kromyon], [Greek: druppa].

[175] Cromyocarpus = Onion fruit; [Greek: kromyon], [Greek: karpos].

[176] Lithatractus = Spindle of silex; [Greek: lithos], [Greek: atraktos].

[177] Druppatractus = Spindle-like olive; [Greek: druppa], [Greek: atraktos].

[178] Stylatractus = Spindle with styles; [Greek: stylos], [Greek: atraktos].

[179] Xiphatractus = Sword-spindle; [Greek: xiphos], [Greek: atraktos].

[180] Cromyatractus = Onion-spindle; [Greek: kromyon], [Greek: atraktos].

[181] Pipetta = Small pipe.

[182] Pipettaria = Pipetta-like.

[183] Spongellipsis = Spongy ellipsoid; [Greek: spongos], [Greek: elleipsis].

[184] Spongurus = Spongy tail; [Greek: spongos], [Greek: oura].

[185] Spongocore = Spongy puppet; [Greek: spongos], [Greek: korê].

[186] Spongoprunum = Spongy plum; [Greek: spongos], [Greek: prounon].

[187] Spongodruppa = Spongy olive-fruit; [Greek: spongos], [Greek: druppa].

[188] Spongatractus = Spongy-spindle; [Greek: spongos], [Greek: atraktos].

[189] Spongoliva = Spongy olive; [Greek: spongos], [Greek: eleia].

[190] Spongoxiphus = Spongy sword; [Greek: spongos], [Greek: xiphos].

[191] Artiscus = Small loaf; [Greek: artiskos].

[192] Stylartus = Bread with styles; [Greek: stylos], [Greek: artos].

[193] Cannartus = Leaf with tubes; [Greek: kanna], [Greek: artos].

[194] Cyphanta = [Greek: Kyphanta], Mediterranean port in Laconia.

[195] Cyphonium = Roundish vessel; [Greek: kyphônion].

[196] Cypassis = [Greek: kypassis]; A girl's girdle.

[197] Cyphocolpus = Vaulted-bosom; [Greek: kyphos], [Greek: kolpos].

[198] Cyphinus = [Greek: kyphinos]; derivation from [Greek: kyphos] = roundish vessel, a kind of fruit.

[199] Cyphinidium = Small Cyphinus; [Greek: kyphinidion].

[200] Cannartiscus = Small loaf with tubes; [Greek: kanna], [Greek: artiskos].

[201] Cannartidium = Small loaf with tubules; [Greek: kanna], [Greek: artidion].

[202] Panartus = quite bread-like; [Greek: panartos].

[203] Peripanartus = Panartus with mantle; [Greek: peripanartos].

[204] Panicium = A kind of bread.

[205] Peripanicium = Panicium with mantle.

[206] Panarium = Bread-basket.

[207] Peripanarium = Panarium (or bread-basket) with mantle.

[208] Ommatocampe = Caterpillar with eyes; [Greek: omma], [Greek: kampê].

[209] Ommatartus = Loaf with eyes; [Greek: omma], [Greek: artos].

[210] Desmocampe = Chain-like caterpillar; [Greek: desmos], [Greek: kampê].

[211] Desmartus = Chain-like loaf; [Greek: desmos], [Greek: artos].

[212] Zygocampe = Caterpillar with paired joints; [Greek: zygon], [Greek: kampê].

[213] Zygartus = Loaf with paired joints; [Greek: zygon], [Greek: artos].

[214] Cenodiscus = Hollow disk; [Greek: kenos], [Greek: diskos].

[215] Zonodiscus = Disk with girdle; [Greek: zônê], [Greek: diskos].

[216] Stylodiscus = Disk with styles; [Greek: stylos], [Greek: diskos].

[217] Theodiscus = Divine disk; [Greek: theos], [Greek: diskos].

[218] Crucidiscus = Disk with cross.

[219] Trochodiscus = Wheel-disk; [Greek: trochos], [Greek: diskos].

[220] Sethodiscus = Sieve-disk; [Greek: sêthos], [Greek: diskos].

[221] Phacodiscus = Lenticular disk; [Greek: phakos], [Greek: diskos].

[222] Periphæna = Shell with transparent girdle; [Greek: periphaina].

[223] Perizona = Shell with surrounding girdle; [Greek: peri], [Greek: zônê].

[224] Sethostylus = Sieve with styles; [Greek: sêthos], [Greek: stylos].

[225] Phacostylus = Lens with styles; [Greek: phakos], [Greek: stylos].

[226] Triactiscus = Shell with three rays; [Greek: triaktiskos].

[227] Sethostaurus = Sieve-cross; [Greek: sêthos], [Greek: stauros].

[228] Phacostaurus = Lens with cross; [Greek: phakos], [Greek: stauros].

[229] Distriactis = Shell with twice three rays; [Greek: distriaktis].

[230] Heliosestrum = Sun-sieve; [Greek: hêlios], [Greek: sêstron].

[231] Astrosestrum = Stellated sieve; [Greek: astron], [Greek: sêstron].

[232] Heliodiscus = Sun-disk; [Greek: hêlios], [Greek: diskos].

[233] Heliodrymus = Sun-forest; [Greek: hêlios], [Greek: drymos].

[234] Astrophacus = Star-lens; [Greek: astron], [Greek: phakos].

[235] Lithocyclia = Circular stone; [Greek: lithos], [Greek: kyklion].

[236] Coccodiscus = Disk with nucleus; [Greek: kokkos], [Greek: diskos].

[237] Stylocyclia = Circular shell with styles; [Greek: stylos], [Greek: kyklion].

[238] Amphicyclia = Circular shell with spines on both sides; [Greek: amphi], [Greek: kyklion].

[239] Trigonocyclia = Triangular shell with circular rings; [Greek: trigonon], [Greek: kyklion].

[240] Staurocyclia = Circular shell with four crossed spines; [Greek: stauros], [Greek: kyklia].

[241] Astrocyclia = Stellated circular shell; [Greek: astron], [Greek: kyklion].

[242] Coccocyclia = Circular shell with nucleus; [Greek: kokkos], [Greek: kyklios].

[243] Diplactura = Stellated shell with double tail; [Greek: diplous], [Greek: aktis], [Greek: oura].

[244] Amphiactura = Stellated shell with tail on both sides; [Greek: amphi], [Greek: aktis], [Greek: oura].

[245] Trigonactura = Triangular shell with three rays; [Greek: trigonon], [Greek: aktis], [Greek: oura].

[246] Hymenactura = Star-shaped shell with membrane between the rays; [Greek: hymên], [Greek: aktis], [Greek: oura].

[247] Astractura = Star-shaped shell with many rays; [Greek: astron], [Greek: aktis], [Greek: oura].

[248] Stauractura = Cruciform shell with four rays; [Greek: stauros], [Greek: aktis], [Greek: oura].

[249] Pentactura = Stellated shell with five rays; [Greek: pente], [Greek: aktis], [Greek: oura].

[250] Echinactura = Echinus-like shell with five rays; [Greek: echinos], [Greek: aktis], [Greek: oura].

[251] Archidiscus = Primordial disk; [Greek: archidiskos].

[252] Axodiscus = Disk with certain axes; [Greek: axis], [Greek: diskos].

[253] Porodiscus = Porous disk; [Greek: poros], [Greek: diskos].

[254] Perichlamydium = Shell surrounded by a mantle; [Greek: peri], [Greek: chlamydion].

[255] Ommatodiscus = Disk with eyes; [Greek: omma], [Greek: diskos].

[256] Stomatodiscus = Disk with openings; [Greek: stoma], [Greek: diskos].

[257] Xiphodictya = Net with swords; [Greek: xiphos], [Greek: diktyon].

[258] Tripodictya = Net with tripod; [Greek: tripous], [Greek: diktyon].

[259] Staurodictya = Cross-net; [Greek: stauros], [Greek: diktyon].

[260] Stylodictya = Net with styles; [Greek: stylos], [Greek: diktyon].

[261] Stylochlamydium = Shell with styles and mantle; [Greek: stylos], [Greek: chlamydion].

[262] Amphibrachium = Shell with two arms; [Greek: amphi], [Greek: brachiôn].

[263] Amphymenium = Shell with veil on both sides; [Greek: amphi], [Greek: hymênion].

[264] Amphirrhopalum = Shell with clubs on both sides; [Greek: amphi], [Greek: rhopalon].

[265] Amphicraspedum = Shell with borders on both sides; [Greek: amphi], [Greek: kraspedon].

[266] Dictyastrum = Reticulated star; [Greek: diktyon], [Greek: astron].

[267] Rhopalastrum = Club-star; [Greek: rhopalon], [Greek: astron].

[268] Hymeniastrum = Membranous star; [Greek: hymên], [Greek: astron].

[269] Euchitonia = Nice shell; [Greek: eu], [Greek: chitônia].

[270] Chitonastrum = Star-shell; [Greek: chitônia], [Greek: astron].

[271] Trigonastrum = Triangular star; [Greek: trigônon], [Greek: astron].

[272] Stauralastrum = Crossed sea-star; [Greek: stauros], [Greek: hals], [Greek: astron].

[273] Hagiastrum = Holy starrulet; [Greek: hagion], [Greek: astron].

[274] Histiastrum = Star with enveloping tissue; [Greek: histion], [Greek: astron].

[275] Tessarastrum = Starrulet with four rays; [Greek: tessara], [Greek: astron].

[276] Stephanastrum = Garland-starrulet; [Greek: stephanos], [Greek: astron].

[277] Dicranastrum = Fork-starrulet; [Greek: dikranon], [Greek: astron].

[278] Myelastrum = Medullary starrulet; [Greek: myelos], [Greek: astron].

[279] Pentalastrum = Little sea-star with five rays; [Greek: pente], [Greek: hals], [Greek: astron].

[280] Pentinastrum = Starrulet with five rays; [Greek: pente], [Greek: inos], [Greek: astron].

[281] Pentophiastrum = Starrulet with five snakes; [Greek: pente], [Greek: ophis], [Greek: astron].

[282] Hexalastrum = Little sea-star with six rays; [Greek: hexa], [Greek: hals], [Greek: astron].

[283] Hexinastrum = Starrulet with six rays; [Greek: hexa], [Greek: inos], [Greek: astron].

[284] Triolena = Shell with three arms; [Greek: tria], [Greek: ôlenê].

[285] Triopyle = With three gate-openings; [Greek: tria], [Greek: pylê].

[286] Triodiscus = Disk with three openings; [Greek: triodiskos].

[287] Pylolena = Disk with alternating gates and arms; [Greek: pylê], [Greek: ôlenê].

[288] Hexapyle = With six gate-openings; [Greek: hexa], [Greek: pylê].

[289] Pylodiscus = Disk with gates; [Greek: pylê], [Greek: diskos].

[290] Discozonium = Disk with girdle; [Greek: diskos], [Greek: zônion].

[291] Discopyle = Disk with gate; [Greek: diskos], [Greek: pylê].

[292] Spongodiscus = Spongy disk; [Greek: spongos], [Greek: diskos].

[293] Spongophacus = Spongy lens; [Greek: spongos], [Greek: phakos].

[294] Spongolonche = Spongy disk with spontoons; [Greek: spongos], [Greek: lonchê].

[295] Spongotripus = Spongy disk with tripod; [Greek: spongos], [Greek: tripous].

[296] Spongostaurus = Spongy disk with crossed spines; [Greek: spongos], [Greek: stauros].

[297] Stylotrochus = Wheel with styles; [Greek: stylos], [Greek: trochos].

[298] Spongotrochus = Spongy wheel; [Greek: spongos], [Greek: trochos].

[299] Spongolena = Spongy disk with two arms; [Greek: spongos], [Greek: ôlenê].

[300] Spongobrachium = Spongy shell with two arms; [Greek: spongos], [Greek: brachiôn].

[301] Rhopalodictyum = Network with clubs; [Greek: rhopalon], [Greek: diktyon].

[302] Dictyocoryne = Net with clubs; [Greek: diktyon], [Greek: korynê].

[303] Spongasteriscus = Spongy star; [Greek: spongos], [Greek: asteriskos].

[304] Spongaster = Spongy star; [Greek: spongos], [Greek: astêr].

[305] Cenolarcus = Hollow basket; [Greek: kenos], [Greek: larkos].

[306] Larcarium = A kind of basket; [Greek: larkarion].

[307] Coccolarcus = Basket with kernel; [Greek: kokkos], [Greek: larkos].

[308] Larcidium = Little basket, diminutive of Larcus; [Greek: larkidion].

[309] Spongolarcus = Spongy basket; [Greek: spongos], [Greek: larkos].

[310] Stypolarcus = Hemp basket; [Greek: stypê], [Greek: larkos].

[311] Larnacilla = Little chest, diminutive of Larnax; [Greek: larnax].

[312] Larnacidium = Little chest, diminutive of Larnax; [Greek: larnax].

[313] Larnacalpis = Tankard-shaped chest; [Greek: larnax], [Greek: kalpis].

[314] Larnacantha = Chest with spines; [Greek: larnax], [Greek: akantha].

[315] Larnacoma = Shell of chest form; [Greek: larnax].

[316] Larnacospongus = Spongy chest; [Greek: larnax], [Greek: spongos].

[317] Larnacostupa = Chest with hemp envelop; [Greek: larnax], [Greek: stupê].

[318] Monozonium = With one girdle; [Greek: monozônion].

[319] Dizonium = With two girdles; [Greek: dizônion].

[320] Trizonium = With three girdles; [Greek: trizônion].

[321] Amphipyle = With one gate on both sides; [Greek: amphi], [Greek: pylê].

[322] Tetrapyle = With four gate-openings; [Greek: tetrapylê].

[323] Octopyle = With eight gate-openings; [Greek: oktô], [Greek: pylê].

[324] Pylonium = Building with gates; [Greek: pylônion].

[325] Amphipylonium = With one large gate on either side; [Greek: amphi], [Greek: pylônion].

[326] Tetrapylonium = Building with four gates; [Greek: tetra], [Greek: pylônion].

[327] Pylozonium = Shell with gates and girdles; [Greek: pylê], [Greek: zônion].

[328] Tholartus = Cupola-bread; [Greek: tholos], [Greek: artos].

[329] Tholodes = Cupola-shaped; [Greek: tholôdês] vel [Greek: tholoeidês].

[330] Amphitholus = Shell with two opposite cupolas; [Greek: amphi], [Greek: tholos].

[331] Amphitholonium = Small shell with two opposite cupolas; [Greek: amphi], [Greek: tholônion].

[332] Tholostaurus = Cross of four cupolas; [Greek: tholos], [Greek: stauros].

[333] Tholoma = Dome-building; [Greek: tholôma].

[334] Alternating, [Greek: metallassôn].

[335] Staurotholus = Cupolas cross-wise disposed; [Greek: stauros], [Greek: tholos].

[336] Staurotholonium = Small shell with cupolas cross-wise disposed; [Greek: stauros], [Greek: tholônion].

[337] Tholocubus = Cube with six cupolas on its sides; [Greek: tholos], [Greek: kubos].

[338] Tholonium = Shell with cupolas; [Greek: tholônion].

[339] Cubotholus = Shell with cupolas disposed on six cube-sides; [Greek: kubos], [Greek: tholos].

[340] Cubotholonium = Small shell with cupolas disposed on the six sides of a cube; [Greek: kubos], [Greek: tholônion].

[341] Zonarium = Small girdle; [Greek: zônarion].

[342] Zoniscus = Elegant girdle; [Greek: zôniskos].

[343] Zonidium = Little girdle; [Greek: zônidion].

[344] Spirema = Convolution, turning; [Greek: speirêma].

[345] Lithelius = Stony sun; [Greek: lithos], [Greek: hêlios].

[346] Larcospira = Spiral basket; [Greek: larkos], [Greek: speira].

[347] Pylospira = Spiral shell with internal gates; [Greek: pylê], [Greek: speira].

[348] Tholospira = Shell with spiral domes; [Greek: tholos], [Greek: speira].

[349] Spironium = Shell with spiral structure; [Greek: speirônion].

[350] Streblonia = Screw-shell; [Greek: streblônion].

[351] Streblacantha = Screw-shell with spines; [Greek: streblê], [Greek: akantha].

[352] Streblopyle = Screw-shell with gates; [Greek: streblê], [Greek: pylê].

[353] Phorticium = Small vessel; [Greek: phortikion].

[354] Spongophortis = Spongy vessel; [Greek: spongos], [Greek: phortis].

[355] Soreuma = [Greek: sôreuma], heap.

[356] Sorolarcus = Basket heap; [Greek: sôros], [Greek: larkos].

[357] Actinelius = Radiant sun; [Greek: aktis], [Greek: hêlios].

[358] Astrolophus = Star-like bunch; [Greek: astron], [Greek: lophos].

[359] Actinastrum = Radiant star; [Greek: aktis], [Greek: astron].

[360] Litholophus = Stony brush; [Greek: lithos], [Greek: lophos].

[361] Chiastolus = With crossed arms; [Greek: chiastos], [Greek: ôlos].

[362] Acanthochiasma = Spine-cross; [Greek: akantha], [Greek: chiasma].

[363] Acanthometron = Spine proportion; [Greek: akantha], [Greek: metron].

[364] Zygacantha = Spines opposite in pairs; [Greek: zyga], [Greek: akantha].

[365] Acanthonia = Spiny article; [Greek: akantha], [Greek: ônia].

[366] Lithophyllium = With stony leaves; [Greek: lithos], [Greek: phyllion].

[367] Phractacantha = Spines enclosed by a hedge; [Greek: phraktos], [Greek: akantha].

[368] Doracantha = Spear-like spine; [Greek: dory], [Greek: akantha].

[369] Astrolonche = Star-spear; [Greek: astron], [Greek: lonchê].

[370] Xiphacantha = Sword spine; [Greek: xiphos], [Greek: akantha].

[371] Stauracantha = Cruciate spine; [Greek: stauros], [Greek: akantha].

[372] Phatnacantha = Spine with fretwork; [Greek: phatnê], [Greek: akantha].

[373] Pristacantha = Saw-spine; [Greek: pristos], [Greek: akantha].

[374] Acanthostaurus = Spine-cross; [Greek: akantha], [Greek: stauros].

[375] Belonostaurus = Needle cross; [Greek: belonê], [Greek: stauros].

[376] Lonchostaurus = Spear-cross; [Greek: lonchê], [Greek: stauros].

[377] Zygostaurus = Pair-cross; [Greek: zygon], [Greek: stauros].

[378] Quadrilonche = Square-spear.

[379] Xiphoptera = Sword-wing; [Greek: xiphos], [Greek: pteron].

[380] Lithoptera = Stone wing; [Greek: lithos], [Greek: pteron].

[381] Amphilonche = With two opposed spears; [Greek: amphi], [Greek: lonchê].

[382] Amphibelone = With two opposed needles; [Greek: amphi], [Greek: belonê].

[383] Acantholonche = Spiny spear; [Greek: akantha], [Greek: lonchê].

[384] Sphærocapsa = Spherical capsule; [Greek: sphaira], [Greek: kapsa].

[385] Astrocapsa = Star-capsule; [Greek: astron], [Greek: kapsa].

[386] Porocapsa = Porous capsule; [Greek: poros], [Greek: kapsa].

[387] Cannocapsa = Tubular capsule; [Greek: kanna], [Greek: kapsa].

[388] Cenocapsa = Hollow Capsule; [Greek: kenos], [Greek: kapsa].

[389] Phractaspis = Hedging shield; [Greek: phraktos], [Greek: aspis].

[390] Pleuraspis = Shield formed by ribs; [Greek: pleura], [Greek: aspis].

[391] Dorataspis = Spear on the shield; [Greek: dory], [Greek: aspis].

[392] Diporaspis = Shield with two pores; [Greek: diporos], [Greek: aspis].

[393] Orophaspis = Roof shield; [Greek: orophos], [Greek: aspis].

[394] Ceriaspis = Dimply shield; [Greek: kêrion], [Greek: aspis].

[395] Hystrichaspis = Porcupine-shield; [Greek: hystrix], [Greek: aspis].

[396] Coscinaspis = Sieve-shield; [Greek: koskinon], [Greek: aspis].

[397] Acontaspis = Shield with spears; [Greek: akontion], [Greek: aspis].

[398] Stauraspis = Cross-shield; [Greek: stauros], [Greek: aspis].

[399] Echinaspis = Urchin with shields; [Greek: echinos], [Greek: aspis].

[400] Zonaspis = Shell with a girdle of shield; [Greek: zônê], [Greek: aspis].

[401] Dodecaspis = Shell with twelve shields; [Greek: dôdeka], [Greek: aspis].

[402] Tessaraspis = Shield with four pores; [Greek: tessara], [Greek: aspis].

[403] Lychnaspis = Lantern-shield; [Greek: lychnos], [Greek: aspis].

[404] Icosaspis = Shell with twenty shields; [Greek: eikosi], [Greek: aspis].

[405] Hylaspis = Forest shield; [Greek: hylê], [Greek: aspis].

[406] Phractopelta = Hedging shield; [Greek: phraktos], [Greek: peltê].

[407] Pantopelta = Shell everywhere with shields; [Greek: pantê], [Greek: peltê].

[408] Octopelta = Shell with eight shields; [Greek: oktô], [Greek: peltê].

[409] Dorypelta = Spear with a light shield; [Greek: dory], [Greek: peltê].

[410] Stauropelta = Cross-shield; [Greek: stauros], [Greek: peltê].

[411] Thoracaspis = Cuirass-shield; [Greek: thôrax], [Greek: aspis].

[412] Belonaspis = Arrow-shield; [Greek: belonê], [Greek: aspis].

[413] Dictyaspis = Net-shield; [Greek: diktyon], [Greek: aspis].

[414] Coleaspis = Shield with sheaths; [Greek: koleos], [Greek: aspis].

[415] Phatnaspis = Panel-shield or fretwork; [Greek: phatnê], [Greek: aspis].

[416] Hexalaspis = Shield with six wings; [Greek: hexalos], [Greek: aspis].

[417] Hexaconus = Shell with six cones; [Greek: hexa], [Greek: kônos].

[418] Hexonaspis = Shield with six auricles; [Greek: hexonos], [Greek: aspis].

[419] Hexacolpus = Shell with six bosoms; [Greek: hexa], [Greek: kolpos].

[420] Diploconus = Double cone; [Greek: diploos], [Greek: kônos].

[421] Diplocolpus = Double bosom; [Greek: diploos], [Greek: kolpos].

* * * * *

Corrections made to printed text

Page iii, § 7: 'Radiolaria' corrected from 'Radioloria'.

Page xiv, § 29: 'Octodendron' corrected from 'Octodendrum'.

Page xvii, § 36: 'allopolar' corrected from 'alloplar'.

Page xxii, § 47: 'rhombic' corrected from 'rombic'.

Page xxvi, § 54B: 'Capsule' corrected from 'Caspule'.

Page xxxiii, § 63: 'Thalassosphærida' corrected from 'Thallassosphærida'.

Page xxxv, § 66.5: 'Nassellaria' corrected from 'Nasellaria'.

Page xlvii, § 77A: 'Mediterranean' corrected from 'Meditteranean'.

Page lxxvi, § 112: 'Phæodinida' corrected from 'Phoeodinida'; 'Cannorrhaphida' from 'Cannorhaphida'.

Page lxxxvi, § 131: Heliosphæra referred to Pl. 28, figs. 1-3 but these are not of this genus.

Page xciv, § 142B: 'Sphærozoea' corrected from 'Sphæozoea'.

Page xcix § 151: Reference to '§ 213' corrected from '§ 273'.

Page cx, § 166: 'interrupted' corrected from 'interruped'.

Page clxxiii, § 249: 'Cannorrhaphida' corrected from 'Cannorrhapida'.

Page clxxix, § 252: 'Karl' (Brandt) corrected from 'Karlt'.

Page clxxxii, § 252: 'Kenntniss' corrected from 'Kentniss'.

Page 29, Thalassosphærida, definition: 'Cannorrhaphida' corrected from 'Cannorhaphida'.

Page 36, Thalassoplancta, definition: 'Cannorrhaphis' corrected from 'Cannorhaphis'.

Page 43, Sphærozoum armatum: 'fig. 9' corrected from 'figs. 1, 9'.

Page 85, Cromyosphæra antarctica refers to Pl. 30, fig. 8 but that does not show this species

Page 87, Genus 26: 'Liosphærida' corrected from 'Liospærida'.

Page 99, Buccinosphæra invaginata, crystals: '0.008' corrected from '0.088'.

Ib., Buccinosphæra tubaria, pores: '0.008 to 0.012' corrected from '0.008 to 0.002' (cf. "three to four times as broad as the bars").

Page 130, Xiphostylus alca: 'Pl. 13' corrected from 'Pl. 14'.

Page 132, Saturnalis annularis, major axis: '0.27 to 0.3' corrected from '0.27 to 0.03'.

Page 137, Stylosphæra jugata, pores: '0.005 to 0.02' corrected from '0.005 to 0.002'.

Page 141, Sphærostylus ophidium, pores: '0.005 to 0.008' corrected from '0.05 to 0.008'.

Page 201, Hexacromyida, definition: 'concentric' corrected from 'concentic'.

Page 203, Cubosphæra concentrica, dimensions (A) and (B): '0.02' and '0.04' corrected from '0.2', '0.4' (cf. the given radial proportions).

Page 222, Coscinomma: 'n. gen.' corrected from 'n. sp.'.

Page 224, Cladococcinus: 'Subgenus' corrected from 'Sugenus'.

Page 241, Heliosoma hastatum, outer pores: '0.006' corrected from '0.06'.

Ib., Heliosoma indicum, outer pores: '0.004 to 0.01' corrected from '0.004 to 0.1' (cf. "twice to five times as broad as the bars").

Page 253, Actinomma japonicum, middle: '0.1' corrected from '0.01'.

Page 260, Pityomma piniferum, middle: '0.05' corrected from '0.5'; inner '0.025' from '0.25'.

Ib., Pityomma drymodes, middle: '0.1' corrected from '0.01'.

Page 261, Cromyomma perplexum, diameter (B): '0.13' corrected from '0.013'.

Page 271, Spongiomma spathillatum: 'Octodendron' corrected from 'Octodendrom'.

Page 291, Cenellipsis ehrenbergii, shorter axis: '0.08 to 0.1' corrected from '0.8 to 0.1'.

Page 307, synopsis, 141: 'Cromyatractus' corrected from 'Cromyotractus'.

Page 308, Druppula cocos, medullary shell: '0.03 and 0.035' corrected from '0.03 and 0.35'.

Page 309, Druppula phoenix, minor axis: '0.08' corrected from '0.8'.

Page 310, Druppula elliptica: 'irregularly' corrected from 'irreguarlly'.

Page 314, Prunulum triplex, minor axis: '0.065' corrected from '0.65'.

Page 324, Druppatractus hippocampus: 'Druppatractus' corrected from 'Druppactractus'.

Page 372, Cyphinidium apicatum, pores: '0.005 to 0.01' corrected from '0.005 to 0.001'.

Page 380, Panartus fusiformis, breadth: '0.08 to 0.1' corrected from '0.08 to 0.01'.

Ib., Panartus profundissimus, pores: '0.015' corrected from '0.15' (cf. "six to eight times as broad as the bars").

Page 405, ref. to Saturnalis: 'Pl. 13, fig. 16' corrected from 'fig. 6'.

Page 418, Trochodiscus solaris: reference to 'Heliodiscus solaster' corrected from 'solaris' per main text entry.

Page 468, Coccocyclia heliantha: 'Coccocyclia' corrected from 'Coccocylia'.

Page 469, Diplactura: reference to 'Spongolena' corrected from 'Spongolene'.

Page 485, synopsis, 236: 'Tessarastrum' corrected from 'Tesserastrum'.

Page 508, Staurodictya ocellata: 'Stylodictya' corrected from 'Stylodicta'.

Page 513, Stylodictya dujardinii: 'Stylodictya' corrected from 'Stylodicyta'.

Page 538: 'Chitonastrum dicranoides' corrected from 'Chitonastrum dicranodes' (per Index).

Page 544, Hagiastrum christi: 'Tessarastrum' corrected from 'Tesserastrum'.

Page 548, subgenus 2: 'Tessarastromma' corrected from 'Tessarostromma'.

Page 557, Pentinastrum, definition: 'Histiastrum' corrected from 'Histriastrum'.

Page 561, last paragraph: 'Archidiscus hexoniscus' corrected from 'Archidiscus hexonicus'.

Page 564, Triolena trispinosa, diameter: '0.55' corrected from '0.55'.

Page 577, Spongodiscus favus, outer meshes: '0.008 to 0.012' corrected from '0.08 to 0.012'.

Page 580, Spongolonche conostyla refers to Pl. 48, fig. 7 which does not show this species.

Page 593, Dictyocoryne trigona: (basal) 'breadth' corrected from 'breath'.

Page 606, first paragraph: 'Actilarcus' corrected from 'Actolarcus'.

Page 606, Cenolarcus: 'Actilarcus' corrected from 'Actolarcus'.

Page 608, Larcarium amphistylum, breadth: '0.12' corrected from '0.012'.

Page 612, Larcidium polyacanthum, medullary shell: '0.03 to 0.09' corrected from '0.3 to 0.09'.

Page 625, Larnacoma quadruplex, breadth (A): '0.016' corrected from '0.16'.

Ib., Larnacoma hexagonium: 'inner cortical and outer medullary' corrected from 'outer cortical and inner medullary'.

Page 632, synopsis: 'Amphipylonium' corrected from 'Amhipylonium'.

Page 654, Octopyle decastyle, breadth: '0.032' corrected from '0.32'.

Page 657, Amphipylonium spinosissimum, length of the inner cortical shell: '0.16' corrected from '0.016'.

Page 657, Amphipylonium tetraceros: 'breadth' corrected from 'breath'.

Page 660, Tholonida: (we distinguish in this) 'family' corrected from 'subfamily'.

Page 665, Tholodes, definition: 'Tholartus' corrected from 'Thalartus'.

Page 666, Amphitholus: 'lentelliptical' corrected from 'lentelleptical'. So also p. 666, Amphitholonium octostylium.

Page 677, pores: '0.004 to 0.008' corrected from '0.04 to 0.008', cf. "once to three times as broad as the bars".

Page 709, Phorticium pylonium, breadth: '0.045' corrected from '0.45'.

Page 742: 'Acanthometron elasticum' corrected from 'Acathometron'.

Page 748, Zygacantha semicompressa, habitat (author): 'Car' corrected from 'Czar'.

Page 765, Phatnacantha: 'Tessaraspida', 'Tessaraspis' corrected from 'Tesseraspida', 'Tesseraspis'.

Page 786, Amphilonche messanensis, length of the minor spines: '0.05 to 0.09' corrected from '0.5 to 0.09'.

Page 826, Coscinaspis rhacopora, diameter: '0.15' corrected from '1.15'.

Page 827, Coscinaspis orthopora: 'Phatnaspis lacunaria' corrected from 'Phatnaspis lacumaria'.

Page 834, Dodecaspis tricinata, diameter: '0.016' corrected from '0.16'.

Page 844, Icosaspis elegans, smaller pores: '0.001 to 0.003' corrected from '0.01 to 0.003'.

Page 852, Phractopelta: 'apophyses' corrected from 'aphophyses'.

Page 867, Coleaspis occulta: 'Coleaspis' corrected from 'Coleapsis'.

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