XIII. CARNIVORA[267]--FISSIPEDIA
ORDER VII. CARNIVORA
This order may be thus defined:--Small to large quadrupeds, terrestrial, arboreal, or aquatic, of usually carnivorous habits. The teeth have generally sharp and cutting edges, and the canines are well developed; the incisors are small, and four to six in number. The number of toes is never less than four. There are usually strong and sharp claws. The clavicles are incomplete or absent. In the hand the scaphoid and lunar bones are always united. The brain is well developed, and the hemispheres are well convoluted. The stomach is always simple, while the caecum, if present, is always small. The members of this group have a deciduate and zonary placenta.
The fewness of the characters used in the above definition is chiefly owing to the fact that the Seals and Sea-lions, although they are referable without a doubt to this order, have undergone in their metamorphosis into aquatic animals so many changes that some of the main features in the structure of their terrestrial relatives have been lost. This group will, however, be again characterised. We shall deal at present with the land division of the Carnivora, the CARNIVORA FISSIPEDIA as they are generally termed. The name is of course given to them to distinguish them from the corresponding division of the PINNIPEDIA. In the latter group the feet and hands are modified into "fins"; in the other the fingers and toes are cleft, as with terrestrial beasts generally. {387}
SUB-ORDER 1. FISSIPEDIA.
FIG. 190.--Under surface of the cranium of a Dog. x 1/2. apf, Anterior palatine foramen; AS, alisphenoid; as, posterior opening of alisphenoid canal; BO, basioccipital; BS, basisphenoid; cf, condylar foramen; eam, external auditory meatus; ExO, exoccipital; flm, flp, foramen lacerum medium and posterius; fm, foramen magnum; fo, foramen ovale; Fr, frontal; fr, foramen rotundum; gf, glenoid fossa; gp, post-glenoid process; Ma, malar; Mx, maxilla; oc, occipital condyle; op, optic foramen; Per, mastoid portion of periotic; pgf, post-glenoid foramen; Pl, palatine; PMx, premaxilla; pp, paroccipital process; ppf, posterior palatine foramen; PS, presphenoid; Pt, pterygoid; sf, sphenoidal fissure or foramen lacerum anterius; sm, stylomastoid foramen; SO, supraoccipital; Sq, zygomatic process of squamosal; Ty, tympanic bulla; Vo, vomer. (From Flower's Osteology.)
A very marked feature of the terrestrial Carnivora is to be found in the structure of the teeth. The incisors are nearly always six, and are somewhat feebly developed in many cases. The canines are almost invariably very large strong teeth, and are always present. In some of the extinct Cats they reached enormous dimensions. The number of cheek teeth is not always identical; but the last premolar in the upper jaw and the first true molar in the lower jaw, known as the "carnassial" or "sectorial" teeth, mark a difference in structure between the anterior and the posterior crushing teeth; those in front of the carnassial tooth have cutting edges, and are often merely small, conical teeth; those behind have broader crowns and are tuberculate; those of simpler forms often trituberculate; those of others {388} with numerous tubercles. The carnassial tooth is often, but by no means always, very much larger and especially longer than the rest of the molar and premolar series. It is less pronounced in some of the omnivorous Arctoidea. The skull of the Carnivora is longer in the more primitive types, such as the Canidae, and shorter in the more specialised Felidae. The orbit is hardly ever completely shut off by bone, though the postorbital process of the frontal sometimes approaches the corresponding upward process of the zygomatic arch. The palate, which is completely ossified, sometimes reaches back for some distance behind the teeth; it always extends as far as the last molar. The tympanic bulla is often very inflated, and if flatter, as in the Bears, is at any rate large and conspicuous. The lower jaw has a high coronoid process, and the condyle is transversely elongated, this part of the bone being rolled into an almost cylindrical form; it fits very closely into the glenoid cavity, and the articulation is thereby very strict--an obvious advantage in a creature with so great a need for power of jaw.
FIG. 191.--A, Atlas of Dog. Ventral view, x 1/2. B, Axis of Dog. Side view, x 2/3. o, Odontoid process; pz, posterior zygapophysis; s, spinous process; sn, foramen for first spinal nerve; t, transverse process; v, vertebrarterial canal. (From Flower's Osteology.)
In the vertebral column the atlas always has large wing-like processes; the spine of the axis vertebra has a long antero-posteriorly elongated form. The transverse processes of the fourth to the sixth cervicals are, as a rule, double. These features, however, though characteristic of the Carnivora are not by any means distinctive. The true sacrum consists of but a single vertebra to which the ilia are attached; but at most two other vertebrae are fused with this. The clavicle is always small and sometimes quite rudimentary, or even absent. The spine of the scapula is well developed, and almost equally divides the {389} surface of that bone. The digits of the Carnivora are mostly five, and are never less than four. The mode of progression may be digitigrade or plantigrade, and the intermediate semidigitigrade mode of walking also occurs. The brain in all Carnivora is large and well convoluted. The arrangement of the convolutions is characteristic. There are three or four gyri disposed round each other, of which the lowest surrounds the Sylvian fissure. The stomach in these creatures is always simple in form, without {390} subdivisions. The caecum is never large, and may be, as in the Bear tribe, completely absent.
FIG. 192.--Brain of Dog. A, Ventral; B, dorsal; C, lateral aspect. B.ol, Olfactory lobe; Cr.ce, crura cerebri; Fi.p, great longitudinal fissure; HH, HH^1, lateral lobes of cerebellum; Hyp, hypophysis; Med, spinal cord; NH, medulla oblongata; Po, pons Varolii; VH, cerebral hemispheres; Wu, middle lobe (vermis) of cerebellum; I-XII, cerebral nerves. (From Wiedersheim's Comparative Anatomy.)
The distribution of the Carnivora is world-wide, excluding only the Australian region, if, as seems probable, the Dingo of that region is an introduced species. The most striking features in their distribution are perhaps the following:--There are no Bears in the Ethiopian region or in Madagascar, and but a single species in the Neotropical. The only Carnivora in Madagascar are the Viverridae, and of the seven genera there found six are peculiar. The Procyonidae are nearly entirely New World in range; out of sixteen genera of Mustelidae only five are New World, and only two of those are peculiar to the American continent. The Hyaenidae are limited to the Old World.
The classification of the Carnivora is a matter which is difficult, and which has therefore been very variously effected. It is unfortunate that the classification of Flower (based upon the researches of H. N. Turner as well as his own, and accepted by Mivart) should fail when applied to fossil forms. For it separates with great clearness the existing genera into three great divisions, the Cynoidea, Aeluroidea, and Arctoidea, definable by visceral as well as by osteological characters. The apparent anomaly, too, of a single supposed Viverrine genus, to wit Bassariscus, existing in America, while all the rest of its kin are Old-World forms, was shown by his characters to be neither an anomaly nor a fact. It will be better, therefore, to divide the Carnivora into the families, Felidae, Machaerodontidae, Viverridae, Hyaenidae, Canidae, Ursidae, Procyonidae, and Mustelidae, indicating at the same time the reasons for and against retaining the three divisions of Sir W. Flower.
FAM. 1. FELIDAE.[268]--This family includes only the Cats (i.e. Lions, Tigers, "Cats," Hunting Leopard, etc.), and is to be distinguished by the following characters:--In the skull the auditory bulla is much inflated, and there is an internal septum; the paroccipital processes are flattened against the bullae. There is no alisphenoidal canal. The dental formula is I 3, C 1, Pm 3 to 2, M 1. The carnassial tooth of the upper jaw has three lobes to the blade; that of the lower jaw is without an inner cusp. {391} The digits are five on the fore-feet, four on the hind. The caecum is present and small. This family contains but two genera, Felis and Cynaelurus.
FIG. 193.--Section of auditory bulla of Tiger. am, Auditory meatus; BO, basioccipital; e, Eustachian canal; ic, oc, two chambers of bulla divided by s, septum; *, their aperture of communication; Pt, periotic; Sq, squamosal; t, tympanic ring. (From Flower's Osteology.)
The genus Felis is very wide in its distribution, being common to both the Old and the New Worlds. Its distinctive characters, as opposed to Cynaelurus, are mainly the following:--The claws are retractile, and the retractility is more markedly developed than in the Cheetah. The molar is not so nearly in a line with the other teeth; the upper carnassial, moreover, has an inner tubercle. The legs are relatively shorter.
The complete retractility of the claws is a very distinctive feature of the true Cats. It is brought about in this way: the terminal joint of the toe, which is clad with the claw, folds back into a sheath by the outer side of or above the middle phalanx. It is held in this position by a strong ligament. The flexor muscles straighten the phalanx which bears the claw, so that the natural position for the animal is to be in a state of retracted claws, which of course preserves them from friction; when wanted for aggressive purposes, they are pulled into sight by the action of the muscles already mentioned.
FIG. 194.--The phalanges of the middle digit of the manus of the Lion (Felis leo). x 1/2. a, The central portion forming the internal support to the horny claw; b, the bony lamina reflected around the base of the claw; ph^1, proximal phalanx; ph^2, middle phalanx; ph^3, ungual phalanx. (From Flower's Osteology.)
Much has been written as to the shape of the pupil of the Cat's eye. Some careful observations upon the matter have been {392} made by Dr. Lindsay Johnson,[269] who found that out of 180 Domestic Cats 111 had round pupils, and that in 19 the shape was a pointed oval, intermediate conditions being offered by the rest. These 180 comprised males and females of many varieties. When the pupil of the Cat's eye contracts, it forms a vertical slit with two pin holes, one at each end, through which alone light appears to enter. In the Genet and the Civet the contraction of the pupil is as in the Cat. In the Lion, Tiger--in fact apparently in all the large Cats--the pupil retains its circular shape even when contraction is fully effected. Dr. Johnson has, furthermore,[270] made some interesting experiments upon the Seal's eye--a creature which has, of course, to exert its powers of vision in two media, and from one to the other. This is effected by dilatation of the pupil when in the water, and its contraction to a vertical slit with parallel margins and rounded ends when in the air, the contraction being to some extent at least under the influence of the animal's will.
The coloration of these creatures is very varied: spots of black, or bordered with black upon a more or less tawny ground-colour, is the prevailing pattern. Stripes are also met with, as in the Tiger, but these are usually cross stripes,[271] while in the related Viverridae there are many examples of longitudinal stripes. Finally, many Cats, as for instance the Puma and the Eyra, are "self-coloured"--have, that is to say, a uniform tint. Just as the unstriped Horse sometimes shows traces of the former existence of stripes, so the self-coloured Cats are occasionally spotted when young; this is markedly so in the case of the Puma; while the Lion is spotted as a cub, and in the adult--particularly in the lioness--there are distinct indications of these spots. It is evident, therefore, that there are grounds for regarding a spotted condition to be antecedent, at least in some cases, to a uniform colour. There are divers explanations of these hues and of these changes. It is held by many that the coloration has a relation to the habits of the creature: the spotted Cats, it is pointed out, are largely arboreal; this is eminently so with the Jaguar at any rate; and in an arboreal {393} creature the spots, it is said, give the impression of flecks of sunlight broken up by foliage. On the other hand, the self-coloured Cats of a sandy to earthen hue assimilate in tint with a sandy or stony soil. The stripes of the Tiger, it is thought, approximate to the tall parallel stems of grasses and other plants in the dense cover in which it lives. In favour of these views is undoubtedly the fact that in other mammals and other animals belonging to quite different groups the same four plans of coloration are met with. Spots and cross stripes are found in the Marsupials; the young Tapir is spotted while the adult is self-coloured, and so forth. This last fact, however, serves to illustrate another view which has been put forward in explanation of these characteristic markings of the Felidae. Eimer has come to the conclusion that there is and has been a regular series of steps in the evolution of these markings. The primitive condition was, he thinks, a longitudinally striped one; the stripes then broke up into spots, and the spots rearranged themselves as transverse stripes; the self-coloured Puma and Lion are a final stage in this gradual evolution. In support of this is the fact that spots precede self-coloration in the individual growth of these animals. The exact sequence of these markings is, however, contradicted by Dr. Haacke's observations upon a certain Australian fish which is cross striped when young and longitudinally striped when adult, a precise reversal of what ought to occur on Eimer's view.
The Felidae are almost universally distributed with the exception, of course, of Australia and a good deal of the Australian region; the headquarters of the group are undoubtedly in the tropics of the Old World.
The characteristics of a few species of the Cat tribe will now be given. As there are at any rate forty-five species, this survey will have to be somewhat incomplete.
The Lion, F. leo, differs from all other species by the mane of the male. It is an inhabitant of Africa, India, and certain parts of Western Asia. Within the historic period it ranged into Europe. According to Sir Samuel Baker those of us who have not seen the Lion in his native haunts have never seen a really magnificent specimen of the brute; but other travellers disagree, and state that a captive Lion is often a finer animal--by reason, of course, of good feeding. Unlike the majority of Cats, the Lion {394} cannot climb. His roar (which is so suggestive, towards its end, of that animal who once dressed himself up in his skin) is literally after his prey. The Lion, it is stated, does not roar except upon a full stomach. The Lion is mainly nocturnal in its habits, and is said to be not in the least dangerous if unprovoked in the daytime; but here again opinions differ. The tail of the animal is provided at the extremity with a slight claw, but it can hardly be sufficient for the animal to lash itself into a fury with it. A Lion will live for thirty or forty years, and will breed freely in captivity. The Gardens of the Zoological Society of Dublin have been famed for their success in breeding Lions; but more surprising still, this has been successfully accomplished in travelling menageries. The "desert" colour of the Lion is familiar to all. It is stated that the likeness to the parched soil of certain parts of Africa is greatly heightened by black patches in the mane, for in certain regions of that continent the arid yellow of the general environment is diversified by pieces of black lava. It is apparently a popular delusion to speak of the Maneless Lion of Guzerat. No doubt maneless Lions do come from there, but so do young and maneless Lions from other places; in short, it is simply a question of age, and old Lions from the Asiatic continent are as fully maned as those from Africa.
The Tiger, F. tigris, is an animal of about the same size as the Lion, distinguished, of course, by the stripes. The skeletons are much like those of other Cats; but the skull of the Tiger may be distinguished from that of the Lion by the fact that the nasal bones reach back beyond the frontal processes of the maxillae. The Tiger is an exclusively Asiatic beast, ranging northward into icy Siberia. The northern individuals have a closer fur, and have been quite unnecessarily separated as a distinct variety. Nine feet six inches is the size of the average full-grown Tiger; but the skins will stretch, a fact of which the sportsman will sometimes take advantage. A "man-eater" is a Tiger which has discovered "that it is far easier to kill a native than to hunt for the scarce jungle game." As with the Lion, the accounts of travellers differ enormously, particularly with regard to the strength of the creature. Some have said that a Tiger can easily lift a full-grown bullock and leap with it in the mouth over a considerable obstacle, a statement which is ridiculed by Sir Samuel Baker. Unlike the Lion, the Tiger can climb trees; {395} it will also voluntarily enter the water, and can swim considerable rivers.
Mr. H. N. Ridley[272] observes that Tigers "habitually swim over to Singapore across the Johore Strait, usually by way of the intermediate islands of Pulau Ubin and Pulau Tekong. They make the passage at night, landing in the early morning. As so much of the coast is mangrove swamp, and the animals do not risk going through the mud, they are only able to cross where the shores are sandy, and thus they have regular starting- and landing-places."
The Tiger is mainly nocturnal, but begins its depredations towards five o'clock in the afternoon, before which it remains sleeping in shady thickets. If the weather is rainy and windy it becomes restless and wanders about earlier. Under the provocation of extreme hunger it will hunt during the daytime. Hunger, too, naturally produces extreme boldness. Mr. Ridley relates a story of four Tigers who walked up the steps of a house in search of the master of the house or his dog, and broke into it, the inhabitants retiring in their favour. The Malays have superstitions about Tigers, which are precisely paralleled by the man-and-wolf stories of Europe. "Certain people are supposed to have the power of turning into tigers for a short time, and resuming their human form at pleasure. The transformation commences tail first, and the human tiger is so completely changed that not only has it all the actions and appearance of the tiger, but on resuming its human form it is quite unconscious of what it has been doing in the tiger state." Mr. Ridley disputes the common stories as to man-eaters. If a Tiger has once tasted human flesh it does not always confine itself afterwards to that article of diet, nor is it only aged and comparatively toothless animals which hunt man. That they do take a large toll of coolies is an undoubted fact, and many are the artifices to prevent the rest from knowing the fate of one of their fellow-workmen, or of becoming acquainted with the presence in the neighbourhood of one of the dreaded beasts.
The Leopard or Panther, F. pardus, is, like the Lion, African and Asiatic in range. The animal is spotted with rosettes of black spots surrounding a central field of the tawny colour of the body generally. Some of the spots are solid and black. "The {396} pantere like unto the smaragdyne" seems to be an inapt description of this Cat, unless indeed the eyes be referred to. The ancients ascribed to it a most fragrant odour. As with the Tiger, a northern variety of this Carnivore has a closer and longer fur. There is a tendency towards melanism in this animal, the black Leopard being comparatively common, particularly, it appears, in high lands. Several other variations in colour are known. These have received different specific names; but it seems that there is in reality but one species of Leopard. The Leopard can climb with the agility of any Cat. Sir S. Baker reserves the name Panther for large Leopards, which reach a length of 7 feet 6 inches. But there is no valid distinction between any two such varieties. The Leopard is as ferocious as the Tiger; and Sir Samuel Baker advises that the power of the human eye be not experimented with when meeting unarmed one of these brutes.
FIG. 195.--Snow Leopard. Felis uncia. x 1/20.
The Snow Leopard or Ounce, F. uncia, is a beautiful creature, confined to the highlands of Central Asia. The ground-colour is white, and the spots are larger than those of the ordinary Leopard. Two examples of this rather rare Carnivore have been recently on view in the Zoological Society's Gardens, London. The Clouded Leopard, F. nebulosa, is an animal of considerable size (6 feet total length). {397}
The Fishing Cat, F. viverrina, of India and China, is about 3 feet 6 inches including the tail. Its black spots upon a grey-brown ground have a tendency to form longitudinal lines. It is in fact, on Eimer's theory, a case of longitudinal stripes breaking up into spots. It differs from the bulk of Cats by preying upon fish, though it is not known how it catches them. It also feeds upon the large snail Ampullaria. In addition to these there are twenty-four species of Cats found in the Old World, mainly in the Oriental region, of small to moderate size.
FIG. 196.--European Lynx. Felis lynx. x 1/12.
The European Lynx, F. lynx, has rather long legs, a short tail, and tufted, pointed ears. It has only two premolars in the upper jaw instead of the usual three. It seems to be doubtful whether the Asiatic Lynx can be distinguished from the European, but the Spanish form, F. pardina, does appear to be distinct. The Common Lynx, sometimes called F. canadensis, also ranges into America, where some other forms exist, known by the specific names of F. rufa and F. baileyi.
In America there are altogether sixteen species of Cats, if we allow three species of Lynx, none of which, however, does Dr. Mivart allow to be different from the European and Asiatic Lynx (F. lynx). {398}
The largest of American Cats is the Jaguar, F. onca. This is an arboreal creature with a long, heavy body and short limbs. Its pelage is much like that of the Leopard, but the spots are larger and more definitely arranged in groups. There are a number of distinct rows of spots. The length of the body alone is not greater than 4 feet. They prey very largely on the Capybara, and upon turtles, which they surprise upon the sand when about to lay their eggs; the reptiles are turned upon their backs, so as to be incapable of escaping, and the Jaguar then easily devours them. The Jaguar will even pursue the turtle into the water, and will devour its eggs and the newly-hatched young.
FIG. 197.--Jaguar. Felis onca. x 1/15.
The Ocelot is another spotted American Cat. F. pardalis[273] ranges from Arkansas in North America southwards, its range corresponding with that of the Jaguar. Although small for one of the "larger cats," the Ocelot inspired with considerable respect Captain Dampier, who remarked of it: "The Tigre-cat is about the bigness of a bull-dog, with short truss, body shaped much like a mastiff, but in all things else, its head, the colour of its hair, the manner of its preying, much resembling the {399} tigre, only somewhat less.... But I have wisht them farther off when I have met them in the woods; because their aspect appears so very stately and fierce."
FIG. 198.--Ocelot. Felis pardalis. x 1/10.
The Puma, F. concolor, the American Lion as it is called in the north, is a rather smaller animal than the last, and of a uniform tawny colour, tending to white on the abdomen and to a dark stripe along the back. The young, as already mentioned, are very distinctly spotted. Like the Tiger, the Puma can endure extremes of heat and cold; it is equally at home in the snow of North America and among the tropical forests and swamps of the south. It is a ferocious creature so far as concerns Deer, Lamas, Raccoons, even Skunks and Rheas, but, according to Mr. W. H. Hudson, will not attack man, and will even defend him against the Jaguar.[274] In captivity the Puma will purr like a Cat.
The Eyra, F. eyra, is another self-coloured American cat, which has a curious likeness to the totally distinct Cryptoprocta of Madagascar.
The Wild Cat of Europe, F. catus, is found over the greater part of Europe, and also in Northern Asia. It was undoubtedly common at one time in this country, though it appears never to have extended its range into Ireland. But the real Wild Cat is now rare in this island, and is confined to certain districts in {400} Scotland. Plenty of alleged wild Cats have been seen and even shot; but these are too frequently merely feral Cats, i.e. domestic tabbies which have reverted to a hunting life. The real Wild Cat differs from the domestic races by the proportionately longer body and limbs, the shorter and thicker tail; the pads of the toes are not quite black. The period of the gestation of the Wild Cat, according to Mr. Cocks, is a week or so longer than that of any domestic Cat.
The Domestic Cat is in fact regarded as the descendant of the Eastern F. caffra, or (perhaps and) the closely-allied F. maniculata. It is highly probable, however, that after introduction into this country as a domestic animal it has interbred with the Wild Cat. Many allied species of Cats will interbreed, even two so far apart as the Lion and the Tiger. There are interesting archaeological and linguistic reasons for regarding the Domestic Cat as an importation. The legend of Dick Whittington's Cat points to it being a rare and valuable animal, which a tamed F. catus would not at that time have been. There was an enactment in Wales of a penalty against him who should kill the king's Cat, again suggestive of its rarity and consequent value. The very name "Puss" is a hint of a foreign origin. Some would derive it from Perse, and upon this is based the notion that the Cat is from Persia. But it seems that Puss is the same as Pasht and Bubastis, showing so far an Egyptian origin for the animal. The ancestral Cats mentioned above are natives of Egypt.[275]
The genus Cynaelurus, which includes but a single species, C. jubatus, the Cheetah or Hunting Leopard, is separated from Felis by a number of characters. In the first place the claws are non-retractile, or at least less retractile than those of the true Cats. It is, moreover, longer legged. The molar is more in a line with the other teeth of the jaw, and the upper carnassial tooth has no inner tubercle. Messrs. Windle and Parsons have lately pointed out many Dog-like features in the muscles. This animal is about as large as a Leopard, but has plain black spots. As its vernacular name implies it is used for sport, and is quite easily tameable. It will purr like the Puma. The Cheetah occurs in India, Persia, Turkestan, and also in Africa; the latter {401} form is sometimes, though quite unnecessarily, separated as C. lanigera. The genus occurs fossil in the Siwalik deposits of India, the species being known as C. brachygnatha.
FAM. 2. MACHAERODONTIDAE.--This is a family of totally-extinct Cats which range from the Eocene down to the Pleistocene. Their general structure is like that of the Felidae; but they differ in a number of skeletal features. Thus there is an alisphenoid canal, and, as in Bears, there is a postglenoid foramen. There is also a distinct carotid foramen, which does not occur in the true Cats. The teeth are often distinguished by the huge size of the superior canines, which are "weapons for penetrating wounds, without rival among carnivorous animals." These must have been displayed at the sides of the chin when the mouth was closed, and it has even been suggested that the animal possessing these exaggerated canines could hardly have properly closed its mouth. The lower canines were often on the contrary much reduced, and in fact incisor-like. In tracing the series of these Cats we find a gradual reduction of the teeth from a more nearly complete number down to the specialised dentition of the existing Cats. The genus Proaelurus, Miocene in range, had four premolars in each jaw, and two molars in the lower and one in the upper. This is the greatest number of teeth found in any member of the group.
The resemblance of this genus to Cryptoprocta has been insisted upon. Archaelurus has suffered a reduction, since one premolar in the lower jaw has disappeared, its formula being thus I 3/3 C 1/1 Pm 4/3 M 1/2. The next stage is shown by Dinictis with three premolars in both jaws. There are a good many species of this genus which are all American and Miocene. This genus has five toes upon the hind-feet, and was probably plantigrade. It had retractile claws.
In the genus Nimravus the dental formula is still further reduced. Another premolar of the lower jaw has gone, the formula being thus I 3/3 C 1/1 Pm 3/2 M 1/2. Nimravus gomphodus was a Carnivore about the size of a Panther. It has no third trochanter upon the femur, which process is present in the corresponding bone of Dinictis. Pogonodon was an equally large animal in which the premolars were three in each jaw, but the molars have become reduced to one in the lower, as they have in this and other genera in the upper {402} jaw. Finally, Hoplophoneus has acquired the dentition of existing Cats.
The Machaerodons, however, show examples with a yet more reduced dentition than that of the most reduced existing Cat, viz. the Lynx, which has only two premolars in each jaw and one molar. In Eusmilus the molar in both jaws is single, and there is but one premolar in the lower jaw.
The genus Machaerodus itself, which appears to include Smilodon, is referred by Cope to the true Cats, and not to the Nimravidae, as he terms the family which we have called here the Machaerodontidae. These creatures are known as "Sabre-toothed Tigers," and were of very wide distribution, occurring in South America as well as in Europe and North America. "As nothing," remarks Professor Cope, "but the characters of the canine teeth distinguished these from typical felines, it is to these that we must look for the cause of their failure to continue. Professor Flower's suggestion appears to be a good one, viz. that the length of these teeth became an inconvenience and a hindrance to their possessors. I think there can be no doubt that the huge canines in the Smilodons must have prevented the biting off of flesh from large pieces, so as to greatly interfere with feeding, and to keep the animals in poor condition. The size of the canines is such as to prevent their use as cutting instruments excepting with the mouth closed; for the latter could not have been opened sufficiently to allow any object to enter it from the front. Even when it opens so far as to allow the mandible to pass behind the apices of the canines, there would appear to be some risk of the latter being caught on the point of one or the other canine, and forced to remain open, causing early starvation. Such may have been the fate of the fine individual of the S. neogaeus, Lund, whose skull was found in Brazil by Lund, and which is familiar to us through the figures of de Blainville."
Machaerodus is placed among the Felidae on account of the fact that the condyloid and carotid foramina unite with the foramen lacerum posterius. But as in at least one species, M. palmidens, there is an alisphenoid canal, which, however, has disappeared in the more recent American forms, it seems permissible to retain the genus in the family Machaerodontidae though its existence reduces the differential character of that family to a minimum. The genus goes back to the Eocene. {403}
FAM. 3. VIVERRIDAE.--The Civets, Genets, and their kind differ from the Cats in a number of points. They form, however, by no means so uniform an assemblage as do the Cats; so that the difficulty is, as Dr. Mivart has remarked, not to divide them into sub-families, but to avoid making too many. But before proceeding to subdivide the family we shall describe the characters of the family and contrast them with those of the Felidae.
All the Viverridae are comparatively small creatures. The head and body are more elongate than in the Cats. The fingers and toes are generally five; but there are some (e.g. Cynictis) where the formula of the toes is as in the Cats, i.e. four on the hind-foot. In the Suricate the fingers are also reduced to four. The claws are perhaps never completely retractile,[276] and often are not at all so. The dental formulae of the genera differ considerably; but in the majority there are more teeth than in the Felidae. The well-known sharp-pointed, conical papillae of the Cat's tongue are not present. The majority have a scent gland beneath the tail, from which the perfume civet is derived. There are a number of osteological characters which differentiate the two families; thus the alisphenoid canal is sometimes present. The bulla is divided, as in the Cats, but is externally constricted.
It seems clear from some at any rate of the characters, i.e. the more complete dentition, the five-fingered hands and feet, the non-retractile claws, etc., that the Civets are on a lower level of specialisation than are the Cats.
SUB-FAM. 1. EUPLERINAE.--The genus Eupleres is in many ways the most aberrant type of Viverrid, and is placed in a sub-family, Euplerinae. Its salient feature is the very peculiar dentition: peculiar in the small size of the canines, the canine-like character of the anterior premolars, and the resemblance of the premolars to molars. In some of the characters of the teeth, Eupleres is Insectivore-like, and was formerly grouped with that family. There are four premolars and two molars in each jaw on each side. It has five toes upon both fore- and hind-limbs; the skull is very slender. It has no alisphenoid canal. The only species, E. goudotii, is of an olive-grey colour, with dark bands across the shoulders in the young. The nose and upper lip are grooved. There are no scent glands. It appears to burrow in the ground, and possibly contents itself with a diet of worms. Eupleres is a {404} native of Madagascar, where all the most peculiar Viverridae live.
SUB-FAM. 2. GALIDICTIINAE.--Mivart has placed in this sub-family the three Mascarene genera, Galidia, Hemigalidia, and Galidictis. In them the orbit is not enclosed by bone; there is no alisphenoid canal, and there are five toes and fingers.
Galidia consists of but one species, G. elegans, of a chestnut brown colour, with a tail ringed with black. The claws are not retractile. The scent gland is absent. There are five digits upon both hand and foot. There are three premolars and two molars on each side of each jaw. The caecum is (for an Aeluroid) long, and pointed at the apex; it is quite twice the length of that of Genetta.
Closely allied to Galidia is the genus Hemigalidia, of which there are two species. It is distinguished from the last genus by the non-annulated tail. It also differs in the dental formula, which is for the molars Pm 4/3 M 2/1. This animal is termed by Buffon the Vansire. He correctly enumerates its grinders, and distinguishes it from the Ferret!
Galidictis is a third genus from Madagascar containing two species, one of which has been unfortunately named G. vittata, leading perhaps to some confusion with the totally distinct Galictis vittata. As in the last two genera the digits are five. The dental formula is that of Galidia. It is distinguished from the other two genera of its sub-family by the longitudinal brown striping of the upper part of the greyish body.
SUB-FAM. 3. CRYPTOPROCTINAE.--Cryptoprocta[277] represents a special sub-family, Cryptoproctinae, and includes only a single species, the Fossa (C. ferox) of Madagascar. It is the largest Carnivore of Madagascar, being about twice the size of a Cat, but with an elongated body; the colour is a tawny brown with no striping. The animal is active and lithe in its motions, and is said to be of almost unexampled ferocity in disposition. Its exact systematic position has been much discussed. By Zittel it is placed in a sub-family (including the extinct Proaelurus and Pseudaelurus) of the Felidae. Mivart and Lydekker, on the other hand, regard it as a genus of the Viverridae. The dental formula of the molars, Pm 3/3 M 1/1, is {405} more like that of the Felidae than of the Viverridae, and the teeth are more Feline in structure. The claws of the feet are retractile. As to internal structure the Fossa agrees largely with the Viverridae, but then this family has no very marked points of difference from the Felidae; but where the anatomy does diverge from that of the Felidae it approaches the Viverridae, especially in the muscular system.
FIG. 199.--Fossa. Cryptoprocta ferox. x 1/6.
The remaining and by far the larger number of genera of Civets are grouped by Professor Mivart in two sub-families: the VIVERRINAE, including the genera Viverra, Viverricula, Fossa, Genetta, Prionodon, Poiana, Paradoxurus, Arctogale, Hemigale, Arctictis, Nandinia, and Cynogale; and the HERPESTINAE, including the genera Herpestes, Helogale, Cynictis, and probably Bdeogale and Rhynchogale. In the Viverrinae the digits are always five, the claws are more or less retractile, the prescrotal scent glands are usually present, and the anus does not open into a sac. On the other hand, the Herpestinae are characterised by the non-retractility of the claws, the absence of the glands in question, and the fact that the anus does open into a terminal sac.
SUB-FAM. 4. VIVERRINAE.--Viverra includes the true Civets. The genus, save for one African species, is Oriental in range. The molar formula is the complete one for the Viverridae, viz. {406} Pm 4/4 M 2/2. The secretion of the prescrotal gland of V. civetta yields the civet of commerce.
The "Rasse," genus Viverricula, has been separated generically from the true Civets. It is, remarkably enough, common to both Madagascar[278] and many parts of the Oriental region. It is, moreover, capable of climbing trees, which its relatives are not. It has no mane like Viverra and is of slighter build.
FIG. 200.--Civet Cat. Viverra civetta. x 1/6.
Prionodon or Linsang differs from the last two genera in the loss of an upper molar. It thus approaches the Cats, with which it also agrees in the furry feet. It is a purely Oriental genus. It also resembles the Cats in that the claws are apparently quite retractile, a feature not common among the group. There are three species of the genus. P. pardicolor has large black spots and a ringed tail. Its body is some 15 inches in length. Dr. Mivart has commented upon the particularly small caecum, which, like that of Arctictis, seems to be on the verge of disappearance.
Genetta, including the Genets, is almost purely African. It has the full tooth formula of Viverra; but is to be distinguished by the absence of a scent pouch, and by a naked strip of skin running up the metatarsus. These animals are all brownish yellowish to greyish with darker spots. The Common Genet, G. vulgaris, is South European, and just gets into Asia; it is also North African. The Genet, an animal "with an appetite for petty carnage," is one of those smaller Carnivora which are possibly to be regarded as meant by the word [Greek: gale], and appear to have "functioned" as Cats among the Greeks. So recently as {407} the times of Belon we are told (by him) that Genets were common and tame at Constantinople.
Poiana, containing a single African species, a spotted and entirely Genet-like animal, has been separated as a distinct genus. Dr. Mivart, however, holds it to be a Prionodon which has acquired a Genet-like tarsus.
Arctictis, containing but one species, A. binturong, the Binturong, is in some ways an exceptional form. It is a black arboreal creature of not very wide range in the Oriental region, with a fully prehensile tail. This feature and its plantigrade foot with naked sole have led to its being regarded as more allied to the Arctoidea. It is, however, undoubtedly an ally of Paradoxurus. The caecum is small, or may be quite absent. The dentition is I 3/3 C 1/1 Pm 4/3 M 2/2. The structure of the animal has been investigated by Garrod.[279]
The genus Fossa is a Viverrine confined to Madagascar. There is but one species, F. daubentoni, the "Fossane." It is distinguished from Viverra by the presence of two bare spots on the under surface of the metatarsus in the hind-limb, and by the absence of a scent pouch. The animal is not much spotted and striped, but the striping in the young is much more marked.
Of the genus Paradoxurus there are some ten or a dozen species, belonging entirely to the Oriental region. The teeth are as in Viverra, but occasionally the molars are reduced to one. The pupils are vertical. The tail though long is not prehensile, "but the animal appears to have the power of coiling it to some extent, and in caged specimens the coiled condition not unfrequently becomes confirmed and permanent" (Blanford). This fact accounts for the name Paradoxurus; for a prehensile tail is hardly to be expected in an animal of the zoological position of the Palm Civets, and yet its occasional twisting led originally to the view that it was so. The genus has scent glands. The dentition is I 3/3 C 1/1 Pm 4/4 M 2/2. P. niger, the Indian Palm Civet, is, like other species, not often to be seen in a wild condition. It is arboreal, and, like other members of the genus, feeds upon a mixed diet, consisting of all kinds of small Vertebrata and insects, varied by fruit. Another species, P. grayi, is so distinctly vegetarian in its habits that it makes considerable havoc in pine-apple beds in the Andaman Islands.
{408}
Arctogale is another Oriental genus with very small teeth, those of the molar series being hardly in contact. The soles of the feet are more naked than in the last genus, and the scent glands, if present, appear to be small and ill developed. It has also a long tail, and is arboreal in way of life. There is "nothing particular recorded" as to its habits. The species are A. leucotis and A. stigmatica.
FIG. 201.--Hardwicke's Civet Cat. Hemigale hardwicki. x 1/5. (From Nature.)
Closely allied to both the last genera is Hemigale, also an Oriental genus. It is to be distinguished from Paradoxurus by having the soles of the feet much less naked, though they are more so than in Viverra or Prionodon. The coloration of the species, H. hardwicki (a Malayan animal), is very peculiar. The body is banded with five or six broad transverse stripes, and the basal portion of the tail is also ringed, an uncommon feature in the group. A second species of this genus is H. hosei, from Borneo. It is blackish in colour, but is not a melanic variety of the last.
Nandinia appears never to possess a caecum.[280] It is also peculiar among Carnivora in the non-ossification of the hinder {409} part of the bulla. It is an African genus, containing two species which are spotted. The tail is ringed.
Cynogale is at any rate a partially aquatic, short-tailed, web-footed, reddish brown-coloured Civet, which lives upon fish and Crustacea, and inhabits the Malay Peninsula, Sumatra, and Borneo. It has long "moustaches," and is said to have a head bearing a singular resemblance to the head of the Insectivorous "Otter" Potamogale. The metatarsus is bald, and the pollex and hallux are very well developed.
SUB-FAM. 5. HERPESTINAE.--There are over twenty species of Herpestes (Mongooses) divided between the Ethiopian and Oriental regions, one species, H. ichneumon, being also found in Europe. The fur has a "pepper and salt" appearance; the feet are plantigrade. There are five fingers and toes. The pollex and hallux are small; the tail is long. The tarsus and metatarsus are usually naked. The Egyptian species "has been injudiciously denominated the Cat of Pharaoh." It is perhaps better known as Pharaoh's Mouse. The beast is so far Cat-like that it will destroy Rats and Mice; and it has been exported to sugar plantations for that very purpose. More famous are its combats with venomous serpents. According to Aristotle and Pliny the Ichneumon first coats its body with a coating of mud, in which it wallows, and then with this armour can defy the serpent. Topsell tells the tale better. The Ichneumon burrows in the sand, and "when the aspe espyeth her threatening rage, presently turning about her taile, provoketh the ichneumon to combate, and with an open mouth and lofty head doth enter the list, to her owne perdition. For the ichneumon being nothing afraid of this great bravado, receiveth the encounter, and taking the head of the aspe in his mouth biteth that off to prevent the casting out of her poison." In the West Indies the animal has been described as fearlessly attacking the deadly Fer de Lance and receiving its bites with impunity; it is also added that it will eat the leaves of a particular plant as an antidote! The real explanation of the result of these encounters is of course the agility of the Ichneumon[281]--fort cauteleuse beste, as Belon says.
Another species, H. albicauda, is distinguished, as the name denotes, by its white tail. A species of this genus, H. urva, {410} sometimes raised to generic rank as Urva, is partly aquatic in habit; it feeds upon crabs and frogs, but is quite willing to take to poultry and their eggs.
Helogale is a genus whose validity appears doubtful (to Dr. Mivart). It is African, and contains two species.
FIG. 202.--White-tailed Ichneumon. Herpestes albicauda. x 1/5.
Cynictis is an African genus, with five digits on the fore-limbs and four on the hind. As in Herpestes, the orbit is completely encircled by bone. There is but a single species, C. penicillata, which is of a reddish colour and has a bushy tail.
Bdeogale, also African, has the toes still further reduced; there are only four on both limbs. The tarsus is hairy and the tail bushy. They are "very rare animals, and nothing is known of their habits." It is known, however, that they will kill poisonous snakes, for Dr. Peters took a Rhinoceros Viper out of the stomach of one.
Rhynchogale[282] differs from all other genera of Viverridae, except Crossarchus and Suricata, in having no groove upon the muzzle. There are five digits. There is the full Viverrine dentition, with five premolars in the upper jaw; but this may be an abnormality.[283]
Crossarchus differs from the last in only having three premolars on each side of each jaw. It is also African, and there are several species.
Suricata is the last genus of Viverridae; it is also African, and contains a single species, Suricata tetradactyla, the "Meerkat" of the Cape. The Suricate has but four toes on each foot; the tarsus and the metatarsus are naked below. The body is banded posteriorly. There are fifteen dorsal vertebrae, and the orbit is {411} closed by bone. The Suricate lives in caves and rock crevices, and will dig burrows. It is distinctly a diurnal animal, and sits upon its hind-legs after the fashion of a Marmot. As Buffon noticed in a tame specimen (thought by him to be a native of Surinam), the animal barks like a dog. The Suricate is largely vegetarian, living upon roots.
FIG. 203.--Suricate. Suricata tetradactyla. x 1/4.
FAM. 4. HYAENIDAE.--Unlike though the Hyaenas appear to be to the last family--mainly perhaps on account of size--they are, nevertheless, very nearly akin to them, more so than to the Cat tribe. It will be remembered that the striping and spotting of the Hyaenas is very Genet- and Suricate-like.
There are admittedly two genera among the Hyaenidae, Hyaena itself with three species,[284] and the Aard Wolf, Proteles, with but one. But Dr. Mivart considers that the Spotted Hyaena should form a genus apart, Crocuta--a proceeding which was initiated by the late Dr. Gray of the British Museum. The Hyaenidae are to be distinguished by the following characters:--There are generally four toes, always so in the hind-foot. The claws are non-retractile. The nose and upper lip are grooved. The molar formula is Pm 4/3 M 1/1. The soles of the feet are covered with hairs upon the tarsus and metatarsus. No scent glands. Tail short. Dorsal vertebrae more numerous than in other Aeluroids, i.e. fifteen. The bulla is divided by a rudimentary septum only.
{412}
FIG. 204.--Spotted Hyaena. Crocuta maculata. x 1/12.
The genera Hyaena and Crocuta, the Striped and Spotted Hyaena respectively, are African and Asiatic in range, Crocuta being limited to South Africa. There is neither hallux nor pollex.
FIG. 205.--Striped Hyaena. Hyaena striata. x 1/12.
The Hyaenas, stigmatised by Sir Samuel Baker as "low-caste creatures," are mainly carrion feeders. Much Arab superstition is associated with them. Certain peculiarities in the structure {413} of the organs of reproduction have led to the belief that a Hyaena changes its sex every year. Its almost human-sounding howls are supposed to be a deliberate trap for the unwary traveller. There is also a legend that in the eye of the Hyaena is a stone which if placed under the tongue of a man endows him with the gift of prophecy.
Proteles presents many resemblances to the Hyaenas, but also certain differences; by many it is placed in a separate family. There is but one species, P. cristata, the Aard Wolf of South Africa. In outward aspect it is very Hyaena-like, the coat being striped, and the ears, though longer, resembling those of a Hyaena. There is also a mane. There are, however, five toes on the fore-feet. The teeth are feebler, particularly the molars, which are also reduced in number. The skull, as in Hyaena, has no alisphenoid canal, but the bulla tympani is divided by a septum. The animal seems to feed largely upon insects, particularly Termites, and also upon carrion.[285]
Of extinct Hyaenoids Ictitherium seems to be transitional between them and the Viverridae. Its dentition, 3/3, 1/1, 4/3, 2/1, is that of a Viverrid, and the feet are five-toed. The upper carnassial tooth, however, is like that of Hyaena in having a strong inner cusp. Other extinct genera of Hyaenas are Lycyaena and Hyaenictis. The genus Hyaena itself goes back as far as to the Miocene, and occurred in Europe until the Pleistocene. The Cave Hyaena of this country seems to be indistinguishable from Crocuta maculata, though it has received the name of H. spelaea.
FAM. 5. CANIDAE.[286]--This family cannot be divided into more than five genera, and is universally distributed with the exception of New Zealand. The auditory bulla is smooth and rounded, and has internally a very incomplete septum, extending through about one-fourth or one-third of the cavity. The meatus has a fairly prominent under lip. The paroccipital process is long and prominent. The mastoid is distinct, though but slightly developed. The glenoid foramen is large; the condyloid foramen is conspicuous, and the carotid canal is deep within the foramen lacerum posterius. The last three characters are Bear-like; the {414} form of the bulla is Aeluroid. The teeth vary somewhat in number, and the following table will serve to indicate the gradual reduction observable in the number of molars:--
Otocyon I 3/3 C 1/1 Pm 4/4 M (3 or 4)/4 Canis generally I 3/3 C 1/1 Pm 4/4 M (3 or 2)/(4 or 3) Cyon I 3/3 C 1/1 Pm 4/4 M 2/2 Icticyon I 3/3 C 1/1 Pm 4/4 M (2 or 1)/2
All the Dogs have a caecum[287] of simple cylindrical form. In C. cancrivorus, C. jubatus, and Nyctereutes procyonides this organ is straight or only very faintly curved; in other Dogs it is coiled into an [288]-like form, sometimes with an additional twist. The Dogs have, as a rule, five toes, one being dropped in Lycaon. The tail is fairly long and distinctly bushy. There is in a number of species a gland at the root of the tail, the presence of which can frequently be detected by the wet appearance due to the oozing secretion. The great majority of existing Canidae belong to the genus Canis. But certainly three, and more doubtfully four, other genera can be distinguished.
The genus Icticyon contains but one recent species, the Bush Dog (I. venaticus, Lund) of British Guiana. The animal has a somewhat Paradoxure-like, at any rate a distinctly un-dog-like, aspect, being longish in the body (some 2 feet long), shortish in the legs, and big-headed. It is blackish in colour, verging towards golden brown on the head and back. Sir W. Flower, to whom we owe our chief knowledge of its structure, characterises it as like a young Fox, and with the playful manners of a puppy. The animal appears to hunt in packs and by scent, and has a reputation for ferocity. Icticyon differs from Canis and agrees with the Indian Cuon in having but forty teeth, the last molar having disappeared from the upper and lower jaws. The caecum, unlike that of the majority of Canidae, is only slightly curved. The brain, oddly enough, shows a Cat-like peculiarity. It has been pointed out that in their long bodies and short legs the genera Cuon and Icticyon resemble the primitive dogs.[289]
A genus Nyctereutes is usually separated from Canis for the inclusion of N. procyonides only. The separation is based upon {415} the strikingly unusual coloration of this Dog. It is a small animal, with numerous long white hairs dorsally. The face, chest, and much of the belly are black. Its aspect distinctly recalls that of a Raccoon,[290] especially in the black patches below the eyes, whence of course the scientific name and the pseudo-vernacular "Raccoon-like Dog." It inhabits China and Japan. As to structure, there is hardly anything that justifies its exclusion from the genus Canis. Garrod, however, mentions the unusually large size of the Spigelian lobe of the liver.
FIG. 206.--Raccoon-like Dog. Nyctereutes procyonides. x 1/6.
Wortman and Malkens[291] have instituted a genus Nothocyon for Dr. Mivart's species C. urostictus[292] and C. parvidens, which are both South American forms.
The genus Otocyon contains but one species, O. megalotis, an African species, ranging pretty widely in that continent (from the Cape to Somaliland, in sandy districts), and sometimes confused with the Fennec on account of its long ears. Its principal structural difference from other Dogs is that there is an additional molar in each jaw, the molar formula being thus M 3/4 or even 4/4. Moreover the carnassial teeth are not so pronounced, and Professor Huxley laid especial stress upon the {416} likeness of some of the cheek teeth to those of the more primitive Arctoids. The angle of the lower jaw is inflected, a character, however, which seems to be more general than is usually allowed among animals not referable to the Marsupials. It is possible that Otocyon is a persistent Creodont-like form which has developed in a direction curiously, and in a most detailed fashion, parallel to the Dogs. If, however, we may assume the addition of the molar, then this anomalous but not necessarily untenable conclusion is obviated.
The genus Cuon, or Cyon, has been instituted for the two or three species of Eastern Dogs (C. primaevus, C. dukkunensis, etc.) which agree with each other in the constant loss of a molar in the lower jaw, or, it should be said, almost constant loss, for the missing tooth is occasionally represented. The latter of the two species mentioned, the Dhole, is, like its congeners, an animal which hunts in packs; it is said to hunt even the ferocious Tiger, and to be thus one of the few animals which can face the largest and fiercest of the Carnivora.
The genus Lycaon is a very distinct type, being differentiated from other Dogs by the possession of only four toes on both fore- and hind-limbs, and by the dental formula, which is Pm 4/4 M 2/3. The one species is L. pictus, the Cape Hunting Dog. It is singularly like a Hyaena[293] in general appearance; the ochraceous grey ground-colour with black markings and the long ears produce this likeness. The animal has got its vernacular name from the habit of hunting in packs. Its range is over a good part of Africa. The occurrence of this species (or at least genus, for the name L. anglicus has been used) in caves in Glamorganshire seems to show that it is a comparatively recent immigrant into Africa. As to its visceral structures, Lycaon[294] does not differ widely from other Dogs. It has, however, no lytta beneath the tongue. The intestines are thus divided: large, 9 feet 1 inch; small, 1 foot 3 inches. This contrasts with the proportions observable in some other Dogs. While other Dogs have but a cartilaginous rudiment of the clavicle, Lycaon has a considerably larger representative of this bone.
FIG. 207.--Fennec Fox. Canis zerda. x 1/5.
FIG. 208.--Prairie Wolf or Coyote. Canis latrans. x 1/8.
The bulk of the Dogs, Wolves, Foxes, and Jackals are thus left over for inclusion in the genus Canis. But the numerous {417} members of this genus can, according to Professor Huxley, be sorted into two series by certain cranial characters. The two series he termed the "Alopecoid" or Fox-like, and the "Thooid" or Wolf-like. It was suggested that the generic name Vulpes be used for the former, and Canis for the second. The characters which will be dealt with immediately are also to be noted among {418} the Dogs belonging to genera that have already been separated off. Thus Lycaon is distinctly Thooid. The characters in question are these:--In the Fox series, the frontal air-sinus of the Thooids is absent; the cranial cavity is pear-shaped, without an abrupt angle coinciding with the supra-orbital sulcus, such as exists in the other group; the coronoid process of the mandible is rather higher and more turned back in the Foxes, while the depth of the mandible at the level of the first molar is greater.
FIG. 209.--Japanese Wolf. Canis hodophylax. x 1/8 (From Nature.)
To the Fox series belong among others the species C. lagopus (Arctic Fox), C. zerda (the Fennec), C. chama (the Silver-backed Fox of Africa), C. virginianus (the Virginian Fox), C. velox (the Kit Fox), and of course the Common Fox of this country. On the other hand, the Dogs proper (such as C. dingo), the Wolves (C. lupus, C. pallipes, C. niger), the Japanese Wolf (C. hodophylax), the Red Wolf of America (C. jubatus), the Jackals (C. aureus, C. anthus, etc.), the Prairie Wolf (C. latrans), and a number of American forms, such as C. azarae, its close ally C. cancrivorus ( = C. rudis), C. antarcticus, C. magellanicus, etc., are decidedly Wolves rather than Foxes. {419}
The Arctic Fox, Canis lagopus, is known by its bluish summer and pure white winter dress as "Blue Fox" and "White Fox" respectively. It is an inhabitant of the Arctic north; but in former days, as its remains show, it descended to such southern latitudes as Germany and this country. The most southern point which it now inhabits is Iceland. This small Fox is well known as being one of the few animals which change their dress to a complete white in winter. This change is, however, not absolutely universal; and M. Trouessart has even stated that the supposed change does not exist, but that the colours are a question of age and sex. This Fox feeds on birds and cast-up carcases of Whales and Seals; it is also said to devour shell-fish, and actually to store up food when abundant for seasons of scarcity. A Fox has been observed to "carry off eggs in his mouth from an eider duck's nest, one at a time, until the whole were removed"; and in winter to "scratch a hole down through very deep snow to a cache of eggs beneath." These anecdotes are told by Sir Leopold McClintock; but others have also asserted the storing habits of this Fox, which really has only a short time of the year in which it can catch suitable living food.
Canis vulpes, the Fox, is not only a native of England, but extends as far to the east as Egypt, the so-called C. aegyptiacus being at most a mere variety. Varieties indeed occur in these islands; the English Fox being redder, the Scotch greyer. Not only is the Fox a truly indigenous English beast, but its remains go back a very long way into past time. Its bones occur in the Red Crag, a deposit of Pliocene times. Its prevalence now is no doubt due to its preservation as a beast of chase. It lives in burrows, either excavating them itself or taking possession of those of some other animal; the Badger suffers in this way, and is said to be vanquished not by the teeth of the burglarious Fox, but by its far fouler habits! It is curious that the expression "foxing" is not so suitable to this animal as to many others. The habit of "shamming death" is a widely-spread one in the animal world, but at least not common with our Fox. The sagacity of the Fox appears to be a little more proverbial than actual; literature teems with its accomplishments. The worthy Archbishop of Upsala, Olaus Magnus, figured Foxes dipping their tails in the streams, and then pulling out inquisitive crayfishes {420} which had seized upon them. "It is a crafty, lively, and libidinous creature," observed a writer of the last century.
Of Jackals there are many species, both African and Oriental. Mr. de Winton allows the following list of African species[295]:--C. anthus, C. variegatus, C. mesomelas, C. lateralis. C. mesomelas is distinguished by the broad black patch in the middle of the back. These animals do not appear to go in packs as so many Canidae do; they live upon carrion, but also rob hen-roosts, and commit other depredations upon the live stock of farmers. The "Quaha," C. lateralis, is distinguished from the last by its sharp bark, and by the obvious side stripe which has given to it its name. It is curious that it should live in apparent amity with C. mesomelas, since the habits of the two are identical and would lead, one might suppose, to a severe struggle for existence, in which one of the two would disappear. Of Indian Jackals C. aureus is the most familiar type.
FIG. 210.--Wolf. Canis lupus. x 1/8.
The European Wolf, Canis lupus, was once, but is no longer, an inhabitant of the British Islands. Their former prevalence is indicated by many names of towns and villages, such as Ulceby and Usselby in Lincolnshire, the town of Wolverton, and Woolmer Forest. In Saxon times Wolves were very abundant; and even so recently as the reign of Elizabeth they were to be seen on {421} Dartmoor and in the Forest of Dean. In the New Forest they were hunted in the twelfth century. It would seem that the last English Wolf was slain some time during the reign of Henry VII. In Scotland, however, they persisted very much longer. So recently as 1743 was the last killed. But before this period they had begun to get exceedingly scarce, for the price of a skin in 1620 is quoted at L6:13:4. In Ireland Wolves lingered yet longer; about 1770 is believed to be the date of their final extinction in that island. The Wolf nowadays is distributed over the greater part of Europe, Northern Asia, and North America, the American form not being considered to be distinct from its European ally. Much legend has collected round this fierce Carnivore. Aristotle, usually accurate in the main, still "states more of wolves than experience warranted." Pliny, unable to sift truth from falsehood, was in this matter "an eager listener to all old women's tales." Aelian added to his marvels and asserted that the Wolf cannot bend its head back; if it should happen to tread on the flower of the squill it at once becomes torpid. So the wily fox, fearing his more powerful enemy, takes care to strew his path with squills! The conversion of men into Wolves was a well-known superstition, dating from Grecian and Roman times; it formed the basis of much of the witchcraft persecutions of the Middle Ages and onwards, and has left its mark in folklore, e.g. the Wolf in "Red Riding Hood."
The Indian Wolves, C. pallipes, C. chanco, and C. laniger, are hardly, if at all, different from C. lupus. Professor Huxley has remarked upon the likeness of C. pallipes to a Jackal, thus bridging over the very inconsiderable gap that may be held to divide Jackals and Wolves.
The Dingo, Canis dingo, is an interesting and somewhat mysterious species of Dog or Wolf. As is well known, it is an Australian species; but it does not seem to be certain whether it was tamed and brought over to Australia by the native races, or is a true and indigenous Australian species.
The colour of this species varies, but is usually of a reddish brown; it is, however, often grey and indeed almost black. Whether indigenous or introduced, the Dingo is a plague to Australian settlers, devouring Sheep, which it generally destroys by tearing out the paunch. It does not as a rule hunt in packs. The Dingo is stated to feign death with so much persistence that {422} an individual has been known to be partly flayed before moving. Dingo remains have been found in river-gravels in Australia where no human remains have been detected. This argues for its indigeneity; but, on the other hand, it has been pointed out that man himself in the Australian continent goes back a very long way into time, and may thus still have imported this companion with him. Anyhow it is quite a wild creature now. Dr. Nehring, an expert investigator into the subject of domestic animals, has stated that the skeleton of the Dingo does not suggest a feral animal at all but a purely wild race.
FIG. 211.--Dingo. Canis dingo. x 1/8.
The Domestic Dog is usually spoken of as Canis familiaris; but to remains in bone caverns the name of C. ferus or C. mikii has been given. There seems to be no doubt that the Dog was the "friend of man" in very early times. Its remains have been met with in Danish kitchen-middens, in the lake-dwellings of the Swiss lakes, and during the Bronze Age in Europe generally. But "there are few more vexed questions in the archaeology of natural history than the origin of the dog." Its remains already referred to may in many cases have argued its use as food. But in a Neolithic barrow a Dog was found buried with a woman, the {423} skeletons of both being in situ; this animal was about the size of a Shepherd Dog. The actual Dog of to-day is divisible into more than 180 different breeds; but in a work upon "Natural History" it would seem out of place to enumerate and characterise these artificial products. Authors vary in their opinion as to what stock gave rise to the domestic races of the past and of to-day. The Jackal, the Bunasu (C. primaevus), the Indian Wolf (C. pallipes), have been proposed as likely ancestors. It is more probable that there is much admixture, and that various wild types have been selected by man in various countries.
EXTINCT CANIDAE.--Many of the existing species of Canidae are also to be found in Pleistocene deposits of the countries which they now inhabit. A few show a wider range in the immediate past than in the present. Thus Lycaon (L. anglicus) has been met with in caves in Glamorganshire, while Icticyon of South America appears to be congeneric with Speothos of the Brazilian caves. The African Otocyon seems to occur in deposits in India. There are also numerous extinct species belonging to the genus Canis, which extend as far back as the Pliocene.
The earlier types of Dogs have been placed in different genera. Cynodictis is an Eocene form from European strata. The skull is decidedly Civet-like, with a short snout. The fore- and hind-feet were five-toed, with well-developed pollex and hallux. The dentition was that of modern Dogs, the molars being two in the upper and three in the lower jaw. The general aspect of the creature and the form of the skeleton was much like that of the Viverrine genus Paradoxurus, of which, as well as of the Dogs, Cynodictis might have been an ancestor.
Simocyon of the Upper Miocene serves as the type of a separate sub-family of Dogs, Simocyoninae. The skull is short, broad, and high; the shortening of the skull affecting the jaws has reduced the teeth greatly; the first three premolars are very small, fall out soon, and are thus often deficient. There are only two molars in each jaw. This type is of course nowhere near the ancestral Dog. It is a much-specialised branch of an early type. Cephalogale is less specialised; there are the usual four premolars. Enhydrocyon is an intermediate form; it has lost one premolar in each jaw.
Amphicyon, forming the type of another sub-family, Amphicyoninae, though usually placed among the Dogs, presents us with {424} many Bear-like features in its organisation. The feet, for instance, were plantigrade and five-toed. The ulna and the radius are specially compared with the same bones in the Bear tribe. The skull on the other hand is as distinctly Dog-like in form. The molars are large, broad, and crushing, and Bear-like. The largest known species, A. giganteus, is of about the size of the Brown Bear. Amphicyon is a Miocene genus. Eocene and allied to it is Pseudamphicyon. This genus has, like Amphicyon, the complete dentition of forty-four teeth. In the Amphicyoninae generally the feet are five-toed, the humerus has an entepicondylar foramen and the femur a third trochanter. The upper molars are large.
The closely allied and American genus Daphaenus has also plantigrade feet, and has in its structure many reminiscences of the Creodonts. So, too, has the Eocene Uintacyon.
Cynodesmus is closely allied to Cynodictis. It has ancient features combined with quite modern ones. The skull is described as being Creodont-like, but the dentition is that of the microdont modern Dogs. In accordance with its age the cerebral convolutions of this Dog are much simpler than in existing Dogs, and the hemispheres do not cover the cerebellum so much.
THE BEAR-LIKE CARNIVORA OR ARCTOIDEA.--That division of the Carnivora which is typically represented by the Bears embraces three recent families, which are united by a number of characters. These Carnivora are always plantigrade or nearly so. They have nearly always five toes. The claws are not retractile, or at most semi-retractile as in the Panda. In the skull the tympanic bulla is often depressed, and is not so globular and obvious as in the Cats. Its cavity is not divided by a septum. The paroccipital processes are not applied to it. The carnassial tooth is less emphasised in this group than in the Cats.
These characters, however, have to be used with caution, as they are hardly universally applicable. A fairly typical Arctoid bulla is seen in such a form as Cercoleptes. The bulla itself is a little more swollen than in Ursus, but it is flattened off in the same way towards the bony meatus. The paroccipital processes, slightly developed, are at a distance of 1/4-inch from the posterior margin of the bulla. In the Raccoon the bullae are much more swollen, and the paroccipital processes are closer to them. In the Marbled Polecat, Putorius sarmaticus, the bullae are fairly {425} swollen, and there is but little flattening towards the meatus: the paroccipital processes, though slight, are in contact with the bullae basally, though their free tips are turned away from them. Finally, in Ictonyx the bullae are much swollen; there is but little flattening towards the meatus, and the paroccipital processes, themselves much swollen, are pressed closely against the bullae. The Mustelidae, therefore, in this as in other characters, approach the Aeluroids.
FIG. 212.--Section of the left auditory bulla and surrounding bones of a Bear (Ursus ferox). am, External auditory meatus; BO, basioccipital; Car, carotid canal; e, Eustachian canal; g, glenoid canal; Sq, squamosal; T, tympanic; t, tympanic ring. (From Flower, Proc. Zool. Soc. 1869.)
There is no caecum, a feature which marks off the Arctoidea from all Carnivora except the Viverrids Nandinia and Arctictis (occasionally). The brain is characterised by the possession of what Dr. Mivart has described as the "ursine lozenge," a tract about the middle of the hemispheres, defined posteriorly by the crucial sulcus, and formed by the emergence on to the surface of the brain of the hippocampal gyrus.
The Arctoidea are very widely distributed. But there are some curious exceptions. Thus there are no representatives of the group (as might be expected) in the Australian region; they are completely absent from Madagascar; while the true Bears (family Ursidae) are totally absent from Ethiopian Africa, and are only represented by a single species, Ursus ornatus, in the Neotropical region.
It is noteworthy that the Arctoidea never show spots or {426} cross stripes (save rings on the tail), which are so common a feature of the coloration of the Cat-like forms.
In bracketing together the three families which are described in the following pages, emphasis is laid upon a number of undoubtedly common features. Palaeontology seems, however, to suggest that the Mustelidae come nearer to the Viverridae. That the Bears and Dogs are connected by extinct annectent genera does not interfere with their present distinctness.
The systematic arrangement of these Carnivora is not easy. It may be useful, however, to give a method of arrangement for the convenient placing of the genera.
The most primitive group is perhaps that of the true Bears, family Ursidae; for in them the molars are two above and three below, and have thus not become diminished in number as in some of the other members of the order. Moreover, the Bears have lobate kidneys, which character, often occurring in the young of animals which when adult have smooth kidneys, may be looked upon as a primitive character. The feet furthermore are completely plantigrade. This family will contain only three genera, Ursus, Melursus, and Aeluropus.
Next comes the family Procyonidae, in several members of which one molar is lost below, though in others the more archaic formula is retained. The kidneys are simple. This family contains the American genera Procyon, Nasua, Bassariscus, Bassaricyon, Cercoleptes, and the Old-World form Aelurus.
The third family, Mustelidae, has the molar formula reduced to 1/2 or 1/1. The kidneys are simple except in the Otters. To this family are assigned the following genera:--Arctonyx, Conepatus, Meles, Mephitis, Taxidea, Mydaus, Mellivora, Helictis, Ictonyx, Mustela, Galictis, Grisonia, Putorius, Gulo, and the aquatic Lutra, Enhydris, and Aonyx.
FAM. 6. PROCYONIDAE.--This family is mainly American in range, the genus Aelurus alone being a native of the Old World. But Zittel would include with the genera of this family the Viverrine and Oriental genus Arctictis, a proceeding which is perhaps hardly admissible, though the occasional absence of a caecum in that animal is so far in favour of such an alliance. The largely vegetable nature of its food and its arboreal habits cause a certain amount of likeness to some of the members of the present group of Carnivores. The Procyonidae have two {427} molars in either half of each jaw. The carnassial teeth are not typically developed, and the molars are broad and tuberculate. The tail is long, often prehensile, and often ringed in the disposition of its colour pattern. The alisphenoid canal is absent save in the aberrant Aelurus. Both condyloid and postglenoid foramina are present. The members of this family are plantigrade.
FIG. 213.--Raccoon. Procyon lotor. x 1/5.
The genus Procyon includes at least two species of Raccoon, the northern form, P. lotor, and the South American, P. cancrivorus. To these may possibly be added a third, P. nigripes. This genus is characterised by the length and the mobility of the fingers, and indeed it uses its hands greatly. It has no median groove upon the muzzle, which is found in many other Arctoids; the ears are moderately large; the tail is not long, being about one-third of the entire length of the animal, including the tail. The soles of the feet are naked. Its limbs are very long (for an Arctoid), and this gives to the animal a bunched-up appearance when walking. There are four premolars and two molars on each side of each jaw. There are fourteen pairs of ribs, of which ten pairs reach the sternum. The latter is composed of nine pieces.
The first-named species has received its name from the fact--of which there is abundant proof--that it dips its food into water. As a matter of fact, the animal frequents the margins of streams, and hunts in the shallow water beneath stones for {428} crayfish, and it also captures fish. Not only is this animal partially aquatic, but it can climb well--"they make their homes in trees, but carry on their business elsewhere." The animal can be readily tamed, but is a tiresome pet on account of its insatiable curiosity and its skill in the use of its hands, which enables it to unlatch doors and generally to pry about everywhere. The Raccoons are mostly nocturnal creatures.
The genus Bassaricyon[296] includes two species, both American, B. alleni being from Ecuador, and B. gabbii from Costa Rica. They have so much the aspect of a Kinkajou that a specimen, which arrived at the Zoological Gardens, was presented and entered as one of those animals. Nevertheless there are many differences between the two genera. The tail of Bassaricyon is not prehensile, and the animal, as will be seen from Fig. 214, has a sharper snout; the brain is more like that of Bassariscus. The likeness to Cercoleptes can hardly perhaps be regarded as an example of "mimicry" since the forms are so nearly related, and the advantage of such an imitation remains to be proved. The muzzle of Bassaricyon is grooved; the ears are fairly large; the soles of the feet are naked; there is but a single pair of teats. There are two molars and four premolars to each half jaw.
FIG. 214.--Bassaricyon. Bassaricyon alleni. x 1/5.
The dorsal vertebrae are thirteen in number; nine of the ribs reach the sternum. The slenderness and convexity of the lower margin of the lower jaw, as well as the feeble angular process, distinguish this genus from its undoubtedly near ally Cercoleptes. The dental formula also is different.
Bassariscus has a ringed tail like a Raccoon, and is also American in range; it furthermore agrees with the Raccoon in {429} being nocturnal and mainly arboreal in habit. There are apparently three species, of which B. astutus is the best known, having been on several occasions exhibited at the Zoological Society's Gardens, the last examples so lately as 1900. The animal was for a long time believed to be allied to the Oriental Paradoxures, and its occurrence in America was therefore puzzling. The real affinities of the creature were, however, definitely set at rest by Sir W. Flower, and later accounts of its anatomy have confirmed this opinion.[297] The vertebrae are more numerous than in Procyon, and the teeth are slightly different; otherwise it presents many likenesses to its nearest ally. The ears are long; the nose is grooved; and the palms and soles are naked.
FIG. 215.--Cunning Bassarisc. Bassariscus astutus. x 1/5. (From Nature.)
The Kinkajou, Cercoleptes, is likewise an American Arctoid. It ranges from Central Mexico down to the Rio Negro in Brazil. It was at one time confounded, and, considering its external appearance, not unnaturally, with the Lemurs. Sir R. Owen dispelled this view by a careful dissection of the creature. Nevertheless, there are certain anatomical features in which it differs {430} from Carnivora and resembles Lemuroids.[298] It has been pointed out that the form of the lower jaw "much resembles that of the Lemuroid Microrhynchus." There is, however, no doubt that it is rightly placed in the present group. The tail is very prehensile, and the animal is therefore, as might be supposed from this circumstance, purely arboreal. It has some twenty-eight vertebrae. This genus has a median groove upon the nose. The claws are long and sharply pointed, and the palms and soles of the feet are naked. The premolars are three, the molars two. There are fourteen dorsal vertebrae, of which nine are united to the nine-jointed sternum by ribs. There is but one species, C. caudivolvulus, of a uniform yellowish-brown colour.
FIG. 216.--Kinkajou. Cercoleptes caudivolvulus. x 1/6.
FIG. 217.--Coati. Nasua rufa. x 1/6.
Nasua, the Coati, ranges from Texas to Paraguay, and has two species. In Guatemala it reaches a height of 9000 feet on the mountains. The nose is produced into a short and very {431} mobile proboscis, hence its name. The native Mexican name for the creature is "Quanhpecotl."
The Coati is largely arboreal, and hunts iguanas in large bands, some of them being on the trees and some on the ground beneath. It also grubs up worms and larvae, for which purpose its long snout is suited. The molars of the genus resemble those of Procyon.
There is not a median groove upon the nose. The palms and soles are naked. Six teats occur. There are thirteen dorsal vertebrae. Nasua nasica[299] and N. rufa are the best known and perhaps the only species. The colour of the fur varies a good deal, and has led to the use of other names for supposed species.
Aelurus, the Panda, is a largish animal found in the south-eastern Himalayas up to a height of 12,000 feet. It has a glossy fur of a reddish colour, and a "white somewhat cat-like face." The molar formula which distinguishes it from the New-World Arctoids belonging to the Procyonidae, as well as from its possible ally Aeluropus, is Pm 3/4 M 2/2. The anatomy of the animal has been described by Sir W. Flower.[300] Dr. Mivart has pointed out that the muzzle though short is upturned in a way distinctly recalling that of Nasua. The animal inhabits forests, and feeds almost entirely upon vegetable food. It eats eggs, however, and insects. Though living to a great extent upon the ground, it is also arboreal, and has sharp semi-retractile claws. It is said to be dull of sight, hearing, and smell, and yet with these disadvantages is also unprovided with cunning or ferocity. Its habits have been compared with those of a Kinkajou.
FOSSIL PROCYONIDAE.--In addition to several of the existing genera, the remains are known of various extinct forms of Procyonidae. Leptarctus, with one species, L. primaevus, is of Pliocene age, but is known only by one ramus of the lower jaw. It appears to "offer a number of transitional characters between the more typical Procyonidae and the aberrant Cercoleptes."[301]
FAM. 7. MUSTELIDAE.--Contrary to what has been stated with regard to the habits of the Procyonidae, the Mustelidae are for the most part "bloodthirsty robbers," and are spread over the {432} whole surface of the world, with the exception of Australia and Madagascar. The molar teeth are generally reduced to one in the upper jaw, and sometimes to one in the lower jaw, which thus gives "a sort of prima facie resemblance to the feline dentition." There is no alisphenoid canal; postglenoid and condyloid foramina are found.
SUB-FAM. 1. MELINAE.--Of this sub-family there are representatives both in the Old and New Worlds.
FIG. 218.--Badger. Meles taxus. x 1/6.
Meles, the Badger, is exclusively Palaearctic in range.[302] Dr. Mivart says that Meles has a relatively longer dorsal region than any other Carnivore, and that it is most nearly approached by its allies Ictonyx and Conepatus. The molar formula is, as in Arctonyx, Mydaus, and Helictis, Pm 4/4 M 1/2. The molars differ from those of any other Carnivore in the much greater size of the first molars than of the last premolars. The nose is not grooved; the soles of the feet are naked. The claws of the fore-feet are much longer than those of the hind-feet.
The genus Arctonyx is a "pig-like badger" from Hindostan, Assam, and North China. The epithet "pig-like" is derived from the long and mobile snout, which is truncated and has terminal nostrils. It is remarkable for having a part of the palate formed by the pterygoids, as in Whales and certain Edentata (e.g. Myrmecophaga). There are sixteen dorsal vertebrae. A. collaris lives in {433} fissures of rocks, or in holes dug by itself. It is a purely nocturnal beast.
The singular genus Mydaus, containing the species M. meliceps, the Teledu or Javanese Skunk, is an inhabitant of Java and Sumatra. It frequents the mountains of these islands, into the soil of which it burrows in search of worms and larvae. There is but one species, which is "like a miniature badger, of rather eccentric colours." It is blackish brown, with a yellowish-white top to its head, and a stripe of the same colour down the back. It may be distinguished by its elongated snout, obliquely truncated, and with inferiorly-placed nostrils. As to osteological characters, it has a more oblique symphysis of the mandible than in any other Carnivore. The secretion of the anal glands is said to rival that of the Skunk in offensiveness and in the distance to which it can be propelled.
SUB-FAM. 2. MUSTELINAE.--Representatives occur in both the Old and New Worlds; but the genera and even the species are in one or two cases common to both.
FIG. 219.--Tayra. Galictis barbara. x 1/7.
Galictis barbara,[303] the Tayra, is a brown, elongated, and Weasel-like animal from Mexico and South America. As is the case with the Weasel, it is sometimes gregarious, a herd of twenty having been observed. The soles of the feet are naked, and the molar formula is Pm 3/3 M 1/2. In these characters the Grison (G. vittata) agrees with G. barbara; but it has been referred to a different genus, Grisonia.
The Grison, "this savage and diabolical-looking weasel," as {434} Mr. Aplin terms it,[304] is known also as the "Huron." It almost rivals the Skunk in the power of the odour which it can emit when enraged. A trapped specimen was placed in a cage 50 yards or so from the house, and even at this distance it was disagreeably easy to tell when any one visited the animal--at least when the wind set in the right direction. It is greyish yellow above and blackish beneath, presenting, as has been remarked, a curious similarity to the Ratel. The nose of this animal is destitute of a median groove, which is present in the Tayra; the soles of the feet, however, are naked as in that animal, and it is nearly plantigrade in walk. It differs also from Galictis in having sixteen[305] instead of fourteen dorsal vertebrae. Eleven of the ribs reach the sternum. Considering the differences that exist between some other genera of Arctoids, it may be fairly allowed that a genus Grisonia is tenable.
FIG. 220.--Grison. Grisonia vittata. x 1/7.
G. allamandi is darker coloured than the Grison, with a white band from the forehead to the neck. Mr. T. Bell described a tame individual as eating eggs, frogs, and even a young alligator.
A third genus of this group has recently been founded by Mr. Oldfield Thomas[306] for a small African animal, which is Grison-like in its coloration. The name given to the genus, Galeriscus, is intended to suggest its likeness to the Grison (Galera or Grisonia). The chief distinctive feature of this genus, whose skeleton is not yet known, is the presence of only four digits on each limb; the pollex and the hallux being entirely absent. The ears of this Grison are short. {435}
The genus Mustela includes the Martens and Sables, which are distinguished from the following genus by the molar formula, which is Pm 4/4 M 1/2. The same character separates them from Galictis, and also the generally hairy under surface of the feet. In more southern latitudes, however, the palms are sometimes naked. The nose is grooved, and the ears are short and broad. The genus is widely distributed, being common to the Old and New Worlds. In the Old World it extends from Europe to Java, Sumatra, and Borneo. The largest species of the genus is the American Pekan, an animal which may be 46 inches in length, including the tail. There are two species of Sable, one European (M. zibellina), the other American.
The only British species of the genus is the Pine Marten, M. martes. It is dark brown, with a brownish-yellow throat, and reaches a length of some 17 inches, with an eight-inch tail. It is getting rare, but is still fairly common in the Lake country. The animal is largely arboreal in habit, whence the vernacular name. It is also called Marten Cat. The allied M. foina, the Beech Marten, has been stated to be, but apparently is not, an inhabitant of these islands. The colour of the animal is a rich brown. It has small eyes and ears and a short tail. The palms of the hands and the soles of the feet are hairy; the muzzle is naked, and has a groove as in Cercoleptes, etc.
The Glutton, Gulo, is a well-marked genus, containing but one species, which is circumpolar in range. The dentition is Pm 4/4 M 1/2. The ferocity but not the voracity of this animal appears to have been exaggerated. It mainly feeds on carcases, and is not really a successful hunter. As to the carcases, Olaus Magnus tells in straightforward language the way in which the animal dilates in size during a meal, and presently, after following the practice of the ancient Romans, returns to the banquet: "Creditur a natura creatum ad ruborem hominum qui vorando bibendoque vomunt redeuntque ad mensam"!
This is one of the few land animals which ranges completely round the pole. There is no difference to be noted between the Old-World and the New-World specimens. It is now an entirely northern form, but in Pleistocene times it reached as far south as this country. The fossil species seems to be Gulo luscus, and to be quite indistinguishable from the living forms.
Putorius, the genus which embraces the Weasel tribe, contains {436} many species known popularly as Weasels, Ermines, Stoats, Ferrets, Polecats, Minks, and Vison. Not only is the genus common to both Old and New Worlds, but in a few cases the species (e.g. P. erminea) range from Asia to America. The molar formula is Pm 3/3 M 1/2. The form of the body is an exaggerated one, the length of the trunk to the limbs being very great. The feet are more or less hairy beneath, and the animals are digitigrade. The nose is grooved. The dorsal vertebrae vary from thirteen to sixteen.
FIG. 221.--Polecat. Mustela putorius. x 1/6.
There are four British representatives of this genus:--
The Polecat, P. foetidus, is a dark brown-coloured animal. Its total length is about 2 feet, of which the tail occupies some 7 inches. It is a species banned by the gamekeeper, and hence is approaching extinction in this country. It is excessively bloodthirsty, as are apparently all the members of this genus, and kills out of mere wantonness. The Ferret is simply a domesticated variety of the Polecat.
The Stoat or Ermine, P. erminea, is reddish brown above, white beneath. In winter, in certain localities, it becomes white with the exception of the black tip of the tail. This colour-change bears some relation to the degree of latitude. It is universal in the north of Scotland, rare in the south of England. As is the case with some other animals that generally change {437} their colour in the winter, there are individuals which seem to have lost the power of change, and others which change in an apparently capricious manner, not influenced by season or cold. Like so many other animals, the Stoat appears at times to migrate, which it does in large parties. Such parties are said to be dangerous, and will attack a man who crosses their path.
The Weasel, P. vulgaris, has much the same colour as the Stoat, but is a smaller animal; it differs also by undergoing no seasonal change. It is equally agile and ferocious, and ought to be encouraged, as it vents its ferocity largely upon Voles and Moles, which it can pursue underground. Like other species of Putorius, it seems to kill its prey by biting through the brain-case.
The fourth British species is the recently-described Irish Stoat, P. hibernicus. It is somewhat intermediate between the last two.
Poecilogale is a genus recently instituted by Mr. Thomas for a small South African Weasel, P. albinucha, coloured like the Zorilla, i.e. with whitish stripes upon black, but differing in its reduced molar formula, which is Pm 2/2 M 1/1 or 1/2.
Lyncodon[307] is thought to be more doubtful; it is South American (Patagonian), with the same molar formula as the most reduced forms of the last genus, i.e. Pm 2/2 M 1/1. The ears are short and almost invisible; the claws of the anterior limbs are long, those of the hind limbs short. It is not quite certain that it is not "an aberrant southern form of Putorius brasiliensis." That its distinction is justifiable appears to be shown by the discovery in the same region of a fossil species, L. luganensis. Matschie places it near Galictis.
The Ratel, Mellivora, is common to India and West and South Africa. It is a black animal with a grey back and grey on the top of the head, the contrast of colour suggesting a dorsal carapace. It runs with a swift trot. The animal lives much on the ground, but can climb trees. It is exclusively nocturnal in its habits. It has the reputation in India of feeding upon dead bodies, a view which has probably no foundation in fact save that it can burrow. The molar formula is Pm 3/3 M 1/1. There are fourteen dorsal vertebrae. The African and Indian species are {438} hardly to be distinguished from each other. The ears are very minute. The tail is short. The muzzle is rather pointed, and the soles and palms are naked.
FIG. 222.--Ratel. Mellivora capensis. x 1/8.
The structure of Helictis has been described by the late Professor Garrod,[308] as well as by Sir W. Flower in his general account of the Carnivorous skeleton. The animal, which is a native of East Asia, is sometimes gaily coloured. H. subaurantiaca, the species dissected and figured by Garrod, is a varied black and orange. The genus is arboreal, and the tail may be moderately long and bushy. The ears are small; the nose is grooved; the palms are naked, but the soles of the feet are hairy. There are fourteen dorsal vertebrae. The molar formula is Pm 4/4 M 1/2.
The Zorilla, Ictonyx, is the last of the Old-World genera of Melinae. It is African, ranging from the tropical parts of the continent to the Cape. "In colour and markings," remarks Dr. Mivart, "as well as in the odour of the secretion of its anal glands, the one or two species which form this genus resemble the skunks; so much so that did they inhabit the same region, and were they devoid of an offensive secretion, they would certainly be said to mimic the skunks." The molar formula of the genus is Pm 3/3 M 1/2. There are fifteen dorsal vertebrae. The nose is grooved and the soles partly hairy.
The American Badger, Taxidea, is a burrower of omnivorous tastes, and correlated with the former habit are the immense {439} claws of the fore-paws. It is North American, but gets into Mexico. The molar formula is as in the American genera Mephitis and Conepatus, and as in the Old-World Ictonyx, and it thus differs from that of Meles. Besides the great size of the claws upon the hand, which are larger relatively than those of any other Carnivore, the genus Taxidea is to be distinguished from all Arctoids (indeed, from all Carnivora) except Mydaus, by the fact that the pelvic limb is of the same length as the pectoral. The muzzle is furry except at the very extremity; this is grooved. The animal is carnivorous, subsisting upon the following very varied kinds of food--"Spermophiles, Arvicolas, birds' eggs, and snails, also honey-comb, wax, and bees."
The Skunk, Mephitis, is an American animal with several species, which range from North to Central America. The black-and-white colour distinguishes the genus, which is furthermore marked by the fact that the third digit of the hand is relatively longer than in any other Carnivore except Taxidea. The soles are partly hairy. It is a terrestrial fossorial animal with well-known powers of protecting itself from aggression. But nevertheless the Skunk has its enemies, and is not quite so unmolested as is sometimes popularly supposed. The Puma, Harpy Eagle, and the Great Horned Owl will at least occasionally attack and devour it. The molar formula is Pm 3/3 M 1/2. There are sixteen dorsal vertebrae.
Conepatus is a more southern form of Skunk, extending down into South America. Its dentition is like that of Mephitis save for the loss of an upper premolar. This genus, which has been further subdivided, differs from Mephitis in the fact that the soles of the feet are wholly naked, whereas in Mephitis those of the hind-limbs are partially hairy. It has no groove on the nose. Its tail is shorter than that of Mephitis. This Skunk has the same habits as the last. In certain parts of South America the animals are so abundant and their odour so powerful that in the evening there is generally a recognisable smell about. This is said to be good for the headache!
SUB-FAM. 3. LUTRINAE.--Of this sub-family there are at least two genera. Enhydris (Latax),[309] the Sea-Otter, is confined to the shores of the North Pacific. It is more purely aquatic than are {440} other Otters. Specimens have been seen swimming fifteen miles from land. The gait of the creature when on land is suggestive of a marine animal; the webbed hind-feet are doubled back upon the knuckles during progression upon land, and locomotion is effected by a series of short springs from these feet; the Otter does not walk "in ordinary acceptance of the term." The tail is flattened, being twice as broad as it is thick, and ends in a bluntish point. Enhydris feeds mainly upon crabs and sea-urchins, but also upon fish. Its dental formula is peculiar by reason chiefly of the reduction of the lower incisors. The formula runs as follows: I 3/2 C 1/1 Pm 3/3 M 1/2.
The molar teeth of this creature, in accordance with its diet, have lost the sharp points of the Mustelidae in general; the crowns are flattened, and the tubercles very blunt. In this it contrasts with Lutra, and presents some resemblance to the Crab-eating Raccoon, Procyon cancrivorus; but the teeth are still further blunted. Enhydris feeds largely upon sea-urchins and shell-fish, and needs blunt teeth for the crushing of the hard shells of its prey. It is interesting to notice that the habits of this animal have been altered by the interference of man. The creature has been hotly pursued for a long time on account of its valuable fur. Instead of feeding and breeding upon the shore in places readily accessible to its pursuers, the Sea-Otter has now taken to the open sea in a greater degree. It utilises masses of floating seaweed for those purposes, and hunts for its food in the deeper water at a greater distance from the shore. In conjunction with the increasing rarity of the Sea-Otter the price of its skin has enormously increased: whereas in 1888 the average price per skin was L21:10s., the value of a fine skin now is at least L100, and as much as L200 and even L250 has been given. The animal is captured by netting and by clubbing and spearing.[310] From the Miocene Siwalik beds remains of an allied form, Enhydridon, have been obtained, whose teeth are somewhat intermediate in their crowns between Lutra and Enhydris.
Lutra, including the Otters, is widely distributed. Both manus and pes are webbed. The ears are small and hairy. The nose is not grooved, and the naked part is very circumscribed; {441} the claws upon the hind-feet are flattened and somewhat nail-like. There are about ten species, but of course, as is so universally the case, a great many more names have been given. The molar formula is like that of Enhydris save that there is an extra premolar in the upper jaw. There are fourteen pairs of ribs, of which eleven pairs reach the ten-jointed sternum. The caudals are twenty-three. The Cape Otter, the "clawless" Otter, has been separated as a genus Aonyx. So too has the South American Pteronura brasiliensis. But in neither case is the separation allowed by Mr. Thomas in a recent revision of the genus.[311] The latter species has the reputation of being very fierce, and is known in Uruguay by the name of "Lobo de pecho blanco." The British species, L. vulgaris, reaches a length of 2 feet or so, with a tail of 16 inches; it ranges over the whole of Europe and a large portion of Asia. This Otter often burrows in the banks of the streams which it frequents; and in the burrow in March or April the female brings forth her young, three to five in number. It will also frequent the sea-coast.
FIG. 223.--Otter. Lutra vulgaris. x 1/6.
FOSSIL MUSTELIDAE.--Besides a number of the existing genera there are fossil members of this family which cannot be referred to existing genera. These latter extend back into time as far as the Eocene. Stenoplesictis, one of these Eocene forms referable to the sub-family Mustelinae, is to be distinguished {442} from living Mustelines by its comparatively long legs. In this genus as in several others there are two upper molars.
FAM. 8. URSIDAE.--This family is nearly universal in distribution, and consists of but three genera, Ursus, Melursus, and Aeluropus.
Ursus has the palms and soles naked except in the Polar Bear, which needs a furry sole to walk with ease upon ice surfaces. The ears are fairly large, and the nose may or may not be traversed by a median groove.[312] The molar formula[313] is Pm 4/4 M 2/3. The brain is naturally (because of the size of the animals of this genus) richly convoluted. The lobate kidneys have already been mentioned in defining this family (see p. 426).
FIG. 224.--Himalayan Bear. Ursus tibetanus. x 1/15.
A very large number of species of Bears have been described. But it is the opinion of Mr. Lydekker[314] and of others that many of these are really to be referred to the European Brown Bear; in this event the Grizzly of North America, the Isabelline Bear, the Syrian Bear, a Bear from Algeria, the Kamschatkan and Japanese Bears, besides the extinct Ursus fossilis of Pleistocene caves, are to be regarded as slight modifications of Ursus arctos. On the other hand, the great Cave Bear, U. spelaeus, {443} and the Thibetan Blue Bear (U. pruinosus) are distinct species, not to be confounded with U. arctos. Neither, of course, are the Peruvian U. ornatus and the Sun Bear, U. malayanus.
FIG. 225.--Malayan Bear. Ursus malayanus. x 1/12.
The Polar Bear has even been placed in a separate genus, Thalassarctos, a proceeding which is quite unnecessary. The white colour of this Bear tends to become browner with age. It is one of the few mammals which extend right round the pole; the Polar Bear is of course a purely Arctic animal. The chief food of the Polar Bear is Seal. Out of thirty Bears examined, Mr. Koettlitz found that only fifteen had animal remains in their stomachs, and these remains were invariably Seal. The animal apparently hunts by scent rather than by sight or hearing, both of which senses seem to be somewhat dull. The males and females wander separately, except of course during the breeding season. The Bears dig holes in which they may remain for some time, but there is no hibernation. In Pleistocene times, the Polar Bear extended as far south as Hamburg. The female has four mammae, pectoral in position.
Melursus includes only M. labiatus, the Sloth Bear of India. This animal has an upturned snout, which is described as closely resembling that of Mydaus, the Teledu. The snout has no groove. {444} All Bears are largely vegetarian and insect feeders; but this Bear is especially so. It delights in the nests of Termites, and its energy in destroying these hills for the sake of their inhabitants is so great that the name of "sloth" appeared to Sir Samuel Baker to be an entire misnomer.
Aeluropus, a rare Carnivore with but one species, A. melanoleucus, is not inferior in size to the Brown Bear, and is distinguished by its largely white coloration. It was discovered in the mountains of East Thibet by Pere David, and described by Milne-Edwards[315] as a distinct and new genus, the discoverer himself having named it as a species of Ursus. It is a vegetable-feeding creature and bulky in form, with a rudimentary tail and a short broad head; in fact, more like a Bear than a Procyonid (with which group it is placed by some). The width of the head, however, is greater than in any other Carnivore; it is most closely approached in this by Aelurus and by Hyaena. The molar formula is Pm 4/3 M 2/3. The soles are hairy. There is no alisphenoid canal. The molars are especially large and multicuspid.
FIG. 226.--Aeluropus melanoleucus. x 1/12.
FOSSIL URSIDAE.--The genus Ursus itself goes back to Pliocene times. The well-known Cave Bear, Ursus spelaeus of {445} Pleistocene times, was one of the commonest of Carnivorous creatures during the very early times of the present era. It was as huge as a Polar Bear or a Grizzly. The skull is remarkable for the fact that the first three premolars, which are small in all Bears, dropped out early in life. An immense number of names have been given to what are in all probability the same species as this Cave Bear of remote antiquity.
Hyaenarctos is the oldest genus of true Ursidae. It goes back into Middle Miocene times, and ranged over Europe and North Africa.
Arctotherium is an American genus of Pleistocene times. The likeness of some of the extinct Canidae to Bears has been already commented upon.
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{446}
Chapter XIV
CARNIVORA (CONTINUED)--PINNIPEDIA (SEALS AND WALRUSES)--CREODONTA
SUB-ORDER 2. PINNIPEDIA
This group includes the Seals, Sea-Lions, and Walruses,[316] all aquatic and, for the larger part, marine creatures. Being aquatic they have to some extent acquired a fish-like form, though not so completely as have the Whales and even the Sirenia. This is most complete so far as the group is concerned in the Seals, where the hind-limbs have become soldered to the tail and are inefficient as walking legs, where the external ears have vanished, and where the general shape of the body is tapering and thus fish-like. The Walruses and Sea-Lions are less modified in this direction; in the latter (not in the former) the external ear, though small, is persistent, and the hind-limbs are capable of being used as organs of progression upon dry land. The general characters applicable to the Carnivora, given upon a previous page, apply to the Pinnipedia.
FIG. 227.--Skeleton of Seal. Phoca vitulina. (After de Blainville.)
The characters confined to the Pinnipedia as a whole are mainly these:--The greater part of the limbs are enclosed within the skin, the hands and feet are fully webbed, and there is a tendency for the nails to disappear, and for the phalanges to increase in number--characters which are clearly not diagnostic of the order but correlated with an aquatic life, since they reappear, and are indeed exaggerated, in the Cetacea. The teeth are peculiar in that the milk dentition is feeble and is early shed. This, as it were, undue emphasis upon one of the two sets of teeth is another likeness to the Whales, {447} where, however, it is the milk dentition that is most pronounced, the "permanent" being feeble and very early shed. But the dentition of the Pinnipedes presents other likenesses to the Cetacea, which are, it must be remembered, regarded by some as a modification of the Carnivorous stock, in which case, of course, the likenesses may be genetic rather than due to adaptation in the two cases. There is a distinct tendency towards a homodont series, the grinding teeth being often very simple, and the very distinct carnassial tooth of many terrestrial Carnivores being absent. Finally, the number of the back teeth shows some signs of being on the increase; and Professor Kuekenthal has found that this increase is due to the division of existing teeth. Here is a point of likeness to the many teeth of the typical Toothed Whales. Dr. Nehring found in several examples of Halichoerus grypus the normal five back teeth increased to {448} six, and the additional molar was at the end of the series, thus suggesting a lengthening of jaw coupled with an increase in number of teeth.
The incisor teeth of the Pinnipedia differ from those of the land Carnivora in that there are nearly always fewer than 3/3, at least in the adult animal. In possessing lobulated kidneys the Pinnipedia differ from all terrestrial Carnivores except the Otters and Bears--a significant fact.
In the characters of the skeleton the Pinnipedia show many peculiarities. The cranial part of the skull is proportionately to the facial part greater than in terrestrial Carnivora; there is no lachrymal bone, and the orbit is to some extent defective in ossification. The alisphenoid canal, so important a feature in the Carnivora, may be present or absent. It is present, for example, in Otaria jubata.[317] This genus also has the more primitive small and rugged tympanic bullae, which are inflated and more Cat-like in others. The vertebrae show an interesting Creodont peculiarity in the complex interlocking arrangements of the zygapophyses of the dorsal vertebrae. The ossicula auditus differ from those of their terrestrial allies in their large size and massive growth. In this they have come to be like those of the Whales and Sirenians.
FIG. 228.--Patagonian Sea-Lion. Otaria jubata. x 1/20.
There is no doubt about their close resemblance to the {449} terrestrial Carnivora, but the question is, to which group of Carnivora have they the most likeness. The semiaquatic Otter, and the still more thoroughly aquatic (marine) Enhydris, suggest an affinity in that direction. The long body and short legs of the Otter, which is more thoroughly at home pursuing fish in the streams than in waddling clumsily upon the banks of the streams, seem to require but little external change to convert it into a small Seal, while the long and completely webbed hind digits of Enhydris are even more like those of a Pinniped. The Sea-Lions, in which the external ear has been preserved, and in which the limbs have not become so entirely useless for progression on the land as they have in the Seals, seem to be the intermediate step in the evolution of the latter. This, however, is not the opinion of Dr. Mivart, who, without definitely committing himself on the point, presents some evidence for the assumption that the marine Carnivora are diphyletic. This double origin, however, is not from two groups of the terrestrial Carnivora. Dr. Mivart, in common with many others, holds that the Pinnipedia as a whole are undoubtedly nearer to the Arctoidea than to either of the two remaining sections of the sub-order. One of the most striking structural characters in which they show this resemblance is the brain; the peculiar Ursine lozenge, already treated of as so distinctive a character of the Arctoidea, is repeated in the Pinnipedia.
There are, however, other points of likeness which seem rather to point to a Creodont origin. Patriofelis is a genus that from more than one side may be looked upon as a possible ancestor of these animals. The Creodont peculiarity of the vertebrae has already been referred to. It may be added that the facial part of the skull is small in Patriofelis, which appears, moreover, to have had an alisphenoid canal. A very remarkable resemblance lies in the structure of the astragalus. This is not deeply grooved on the tibial facet as it is in Fissiped Carnivora. This might be held to be an instance of degeneration in the aquatic Seals, which do not use their limbs as walking organs. But Professor Wortman[318] has pointed out that in the Sea-Otter, which is entirely aquatic, the groove exists and is plain. The likeness offered to the Seals by the spreading feet of Patriofelis is noticed under the description of that genus.[319]
{450}
FIG. 229.--Cape Sea-Lion. Otaria pusilla. x 1/16.
FAM. 1. OTARIIDAE.--The family Otariidae[320] is no doubt the least modified of the aquatic Carnivora. It is rational, therefore, to commence the survey of the group with this family. They have preserved, as already noted, the independence of the hind-limbs; the external ear is present, though small; there is an obvious neck, and the nostrils are at the end of the snout, as in terrestrial creatures generally. The nails are small and rudimentary, save those upon the three middle digits of the foot. It is a singular fact that among the Otaries the angle of the lower jaw is "inflected as much as in any Marsupial." The literature relating to this family is great, and it seems difficult to reconcile the very varying opinions as to how many genera ought to be admitted. Mr. Allen arranged the nine species which he allowed {451} in six genera; but more generic names have been proposed. At the other extreme stands Dr. Mivart, who speaks of only one genus, Otaria; of this genus the number of species is by no means agreed upon. There can, however, be no doubt of the distinctness of the Northern Fur Seal, O. ursina (the "Seal" of commerce and the cause of international complications), of the Patagonian Maned Sea-Lion, O. jubata,[321] of O. pusilla of the Cape, of the Californian O. gillespiei, of O. hookeri from the Auckland Islands, and of four or five others. The range of the genus is wide, but is mainly Antarctic. It is usual to speak of "Hair Seals" and "Fur Seals," the latter being the species which produce the "sealskin" of commerce. The difference is that in the Fur Seals there is a dense, soft under-fur, which is wanting in the other group. It is, however, impossible to make this character the basis of a generic subdivision. There is a Fur Seal, O. nigrescens, in South America as well as the more widely-known northern form.
FAM. 2. TRICHECHIDAE.--This family contains but one genus, Trichechus, the Walrus or Morse, or Odobaenus, as the more correct term seems to be. It is a tiresome result of accurate conformity with the rules of priority in nomenclature that the name Trichechus should be applied to the Manatee. There is but one species of Walrus, though it has been attempted to show that the Pacific and Eastern forms are different. The animal is Arctic and circumpolar. The Walrus is characterised by the enormous canines of its upper jaw, which form the well-known tusks and reach a length of 30 inches. The animal can progress on land like the Sea-Lions; but, as in the Seals, there are no external ears, though there is a slight protuberance above the meatus auditorius. The strong bristles upon the upper lip are as thick as crow quills. The pectoral limb has nails, but these are small, as in the Sea-Lions. The under surface of the manus has a warty pad, which cannot but assist[322] in maintaining a foothold upon slippery ice. The hind-limbs have longer nails, which are still diminutive and subequal in size. There is no free tail. The liver of this animal is much furrowed, but not so much so as in Otaria, though more so than in Phoca. The kidneys are of course lobulate, as in the other aquatic Carnivores. The milk dental formula appears to be I 3/3 C 1/1 Pm + M 5/4. In the adult the formula[323] is I 1/0 C 1/1 M 3/3.
{452}
FIG. 230.--Common Seal. Phoca vitulina. x 1/8. (From Parker and Haswell's Zoology.)
FAM. 3. PHOCIDAE.--The true Seals have no external ears, and the nostrils are quite dorsal in position as in other aquatic animals, such as the Crocodile. There is obviously an approach to the conditions characteristic of the Whales. The hind-limbs are useless for locomotion on land. They are bound up with the tail, and form functionally merely a part of the tail. In this family there are, at any rate, eight genera.
Phoca and Halichoerus are not very wide apart from each other. In both there are five well-developed claws on feet and hands. They are British, and generally Arctic and temperate in range. For some reason or other the late Dr. Gray placed Halichoerus in the same sub-family with the Walrus! Phoca is not only marine, but is found in the Caspian and in Lake Baikal. Their existence in those inland seas is believed to be a vestige of a former connexion with the sea. Halichoerus grypus is a large seal 8 feet in length when full grown. Its colour is yellowish grey, with darker grey spots and blotches. It is not uncommon on the shores of our islands, particularly of the Hebrides and Argyllshire. The commonest Seal is Phoca vitulina, not more than 4 to 5 feet long, and of the same spotted coloration as the last. This Seal has, however, a much wider distribution, being Arctic as well as British, American, and North Pacific. A curious fact about this Seal is that it is not impatient of fresh water; not only will it ascend rivers, but it will live in inland lakes. It is said to be especially sensitive to musical sounds. P. hispida is British, but a rare visitor to our islands. It is essentially an Arctic species. The Harp Seal, P. groenlandica, is so called on account of a harp-shaped black bar in the males, which starts at {453} the shoulders and extends to the thighs. Like the other Seals mentioned, the young are white when first born. As may be inferred from its scientific name this species is also Arctic in range. It is also a rare visitor to these shores.
The genus Cystophora is the only other genus of which there is a British representative. It is called the Hooded Seal on account of an inflatable sac upon the face, with which it is said to attempt to terrify its enemies. The genus has an incisor less in each half of each jaw than Phoca and Halichoerus. Its formula is I 2/1 while these genera are both 3/2. C. cristata is a large species reaching a length of 10 feet. The colour of the back is dark grey with deeper coloured spots. A few individuals only have been recorded from our coasts.
Stenorhynchus ( = Ogmorhinus) is an Antarctic genus. The hind-feet are clawless. The incisors are 2/2. The molars have an additional cusp, i.e. three in all.
The genus Leptonyx with but one species, L. weddelli, is purely Antarctic in range. Like the last genus it has two incisors, and has but rudimentary claws upon the hind-feet; the first and fifth toes moreover are the longest. The genus chiefly differs from the last in the simple conical crowns of the molars, which have not the additional cusps of Stenorhynchus.
Ommatophoca is another Antarctic genus with but a single species, O. rossi. In this genus the hind-feet have no claws, and the first and fifth toes are longer than the others. The claws of the fore-feet are rudimentary. The immense size of the orbits gives the name to the genus. There are two incisors, and the molars are all very small.
Monachus is a northern genus inhabiting the Mediterranean and the Atlantic in the vicinity of Madeira and the Canary Islands. It has rudimentary nails upon both pairs of feet. The first and fifth toe of the hind-feet are longer than the others. As with the preceding genera, the incisors are two in each jaw. The species are M. albiventer, the Monk-Seal, and M. tropicalis, the Jamaica Seal.
Allied to Cystophora is the genus Macrorhinus, with (possibly) two species, of which one is Antarctic, the other frequents or frequented the coast of California. The incisors are two in the upper jaw, and but one in the lower. The premolars are four and the molar one; all the teeth are small and simple, but {454} have long roots. The nose of the male has a dilatable proboscis. The southern Elephant Seal is M. leoninus, and reaches a length of some 20 feet. It occurs on the shores of Kerguelen and some other more or less remote islands. Its habits have been studied and described by several observers, beginning with Anson in the last century. The late Professor Moseley gave a good account of this marine monster in his book on the voyage of the "Challenger." When the animal is enraged, the end of the snout is dilated; but when this happens there is no long and hanging proboscis such as has sometimes been described. The inflation affects the skin on the top of the snout, which thus rises rather upwards during inflation. The inflated region, according to Mr. Vallentin, quoted by Mr. J. T. Cunningham, is about 1 foot long in an individual of 17 feet. It has been stated that this proboscis is a temporary structure, only appearing in the breeding season; but recent observations have shown that this statement is inaccurate; it persists all the year round. The males fight greatly during the breeding season, and produce a roar which has been compared to the "noise made by a man when gargling." The females and the young males bellow like a bull. The males fight of course with their teeth, literally falling upon one another with their whole weight. Mr. Cunningham thinks that the use of the proboscis is to protect the nose from injury; or that it may be merely the result of "emotional excitement." In any case the Bladder-nosed Seal, Cystophora, is undoubtedly protected from injury by the possession of a corresponding hood. The nose is the most vulnerable place, and the existence of this hood would stave off the effects of a blow in that region. Moseley, however, has said of Macrorhinus that it cannot be stunned by blows on the nose as other Seals can; but he attributes this, not to the dilated snout, but to the bony crest on the skull, and to the strength of the bones about the nose. This Seal crawls with difficulty on the land, and as the animals move "the vast body trembles like a great bag of jelly, owing to the mass of blubber by which the whole animal is invested, and which is as thick as it is in a whale."[324] When lying on the shore, these animals scrape sand and throw it over themselves, apparently to prevent themselves from being {455} incommoded by the direct rays of the sun, to the effects of which they are very susceptible. The Elephant Seal is mild and inoffensive, unless enraged, and, of course, during the breeding season.
ORDER VIII. CREODONTA.
This entirely extinct group of Mammalia may be thus characterised:--Small to large carnivorous mammals, with skull on the whole like that of the Carnivora and with trenchant teeth; digits with unguiculate phalanges; tail long; extremities usually with five, sometimes with four digits. In the carpus a centrale is present, and the scaphoid and lunar are separate. Interlocking of posterior dorsal and lumbar zygapophyses very perfect. Brain small but convoluted.
This group, which corresponds with the CARNIVORA PRIMIGENIA of Mr. Lydekker, is not easy to separate absolutely from the existing and more especially from some of the extinct members of the CARNIVORA VERA. They also come exceedingly near the Condylarthra, the presumed ancestors of the Ungulata, and like them begin in the earliest Tertiary deposits. Their likeness to the carnivorous Marsupials has also been insisted upon; but it would seem that the succession of teeth in the Creodonta is typically Eutherian.
The characteristics of the group may be exemplified by an account of the genus Hyaenodon, after which some of the more important deviations in structure shown by other genera will be referred to.
Hyaenodon is both American and European, and ranges through the Eocene and the Upper Miocene. It is a much-specialised Creodont, and therefore exhibits well the distinctive characters of the group. About a dozen species have been described. One of the best-known is the American H. cruentus, and the following description refers to it. The back part of the skull is low and broad, and is compared by Professor Scott (who has described this and other species) as being "somewhat like that of an opossum."[325] The whole skull is {456} long, and the top has a great sagittal crest. The paroccipital processes are short and are closely applied to the mastoid processes. The mesethmoid is larger than in the carnivorous Marsupials, and the frontals are very large. The palate has a peculiar structure; in most species the hinder ends of the palatines are separated by a narrow fissure which broadens gradually, thus forming the posterior nares. In H. leptocephalus the posterior nares are brought very far back by the meeting of the alisphenoids. The presphenoid, contrary to what we find in the Dog, for example, is chiefly concealed by the vomer, which covers it. The mandible has a long and strong symphysis, and its angle is not inflected. The fore-limb is described as being "weak when compared with the modern Carnivora." The scaphoid and lunar are separate, and there is a centrale. The teeth present us with nearly the typical formula. There is only one molar missing in the upper jaw. The canines are enlarged. It has been suggested from a consideration of its palate that Hyaenodon was a semiaquatic animal; the deep cleaving at the extremities of the phalanges seems to point in the same direction, since they resemble in this the genus Patriofelis, which there are other reasons to regard as aquatic. This latter genus has a fore-limb which is very like that of the Pinnipedia, the digits are much spread out, and would seem to have supported a kind of paddle. In any case it certainly fed upon aquatic tortoises, for their remains have been found in its coprolites. The name Limnofelis, also applied to what appear to have been members of this genus, is suggestive of their habits. Patriofelis, at least one species, seems to have been of about the size of a Lion.
Mesonyx has a brain case which is actually smaller than that of the Marsupial Thylacinus. The lachrymal bone is very large, and extends a little way over the face, as is also the case with Hyaenodon; this condition is also found in Insectivora and in Thylacinus. The axis vertebra has a curiously-shaped spine, which is very different from the hatchet-shaped process of that vertebra usual in the Carnivora, but is not unlike what exists in the Arctoid genera Meles and Mydaus. The limbs show much disparity in length, and seem to argue a much-arched back when the creature progressed. The carpus is stated to be strikingly like that of the Insectivora. There is as in other Creodonts a separation between the scaphoid and lunar; {457} the centrale appears to be present. The pelvis "is most like that of the bear," the metacarpals and the tibia, and some other bones, resemble those of the Hyaena. In fact this animal shows those combined characters which are common in archaic forms.
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{458}
XV. RODENTIA--TILLODONTIA
ORDER IX. RODENTIA[326]
Small to moderately large animals, furry, sometimes with spines. Toes with nails of a claw-like character, or sometimes approaching hoofs. Usually plantigrade, and only occasionally and partly carnivorous. Canine teeth absent; incisors long and strong, growing from persistent pulps, and with enamel only or chiefly on the anterior face, producing a chisel-shaped edge; molars few (two to six), separated from the incisors by a wide diastema. Caecum (nearly always present) very large, and often complicated in structure. Brain, if not smooth, with few furrows, the hemispheres not overlapping the cerebellum. Surface of skull rather flat; orbits not separated from temporal fossae; malar bone in middle of zygomatic arch; palate very narrow, with elongated incisive foramina; articular surface for lower jaw antero-posteriorly elongated. Clavicles generally present. Testes generally abdominal. Placenta deciduate, and discoidal in form.
The Rodents are a very large assemblage of usually small, sometimes quite minute, creatures, embracing an enormous number of living generic types. They are distributed all over the world, including the Australian region, and, being small and often nocturnal, and by no means particular in their diet, have managed to thrive and multiply to a greater extent than any other group of living mammals. They are chiefly terrestrial creatures, and often burrow or live in ready-made burrows. {459} Some, however, such as the Voles, are aquatic; others, e.g. the Squirrels, are arboreal, and there are "flying" Rodents exemplified by the genus Anomalurus. Their range of habitat is in fact as wide as that of any other Order of mammals, and wider than that of most.
FIG. 231.--Side view of skull of Cape Jumping Hare (Pedetes caffer). x 3/5. AS, Alisphenoid; Ex.O, exoccipital; Fr, frontal; L, lachrymal; Ma, malar; Mx, maxilla; Na, nasal; OS, orbito-sphenoid; Pa, parietal; Per points to the large supratympanic or mastoid bulla; PMx, premaxilla; Sq, squamosal; Ty, tympanic. (From Flower's Osteology.)
The most distinct anatomical characteristic of the Rodents concerns the teeth. They are without exception entirely deprived of canines. Thus there is a long diastema between the incisors and the molars. Another peculiarity is, that in many cases the dentition is absolutely monophyodont. In such forms as the Muridae there seems to be no milk dentition at all. In that family there are only three molars; but in other types where there are four, five, or six molars, the first one, two, or three, as the case may be, have milk predecessors, and may thus be termed premolars. This has been definitely proved to be the case in the common Rabbit, which has the unusually large number of six grinding teeth in each half of the upper jaw when adult. The first three of these have milk forerunners. On the other hand the existence of four molars does not apparently always argue that the first is a premolar; for Sir W. Flower found that in Hydrochoerus,[327] none of the teeth had any forerunners, at any rate so far as could be detected from the examination of a very young animal. The Rabbit appears to be also exceptional, in that the second incisor of the upper jaw and the incisor of the lower jaw have milk forerunners. In any case the tendency towards monophyodontism is peculiarly well-marked in this group of mammals. The incisors of Rodents are as a rule in each jaw a single pair of long and strong teeth, which grow from persistent pulps, and {460} grow to a very great length, extending back within the jaw to near the hinder part of the skull. These teeth are reinforced in the upper jaw by a small second pair in the Lagomorpha only. The incisors are chisel-shaped, and often brown or yellow upon the outer face, as is the case also with some Insectivores. This peculiar shape, and their strength, renders them especially capable of the gnawing action which characterises the Rodents. It has been pointed out that where the incisors are wider than thick, the gnawing powers are feebly developed; and that on the contrary, where these teeth are thicker than wide, the animals are good gnawers. The incisors have often an anterior groove, or it may be grooves.
FIG. 232.--Molar teeth of Rodents. A, of Capybara (Hydrochoerus); B, of Squirrel (Sciurus); C, of Ctenodactylus. (After Tullberg.)
The cheek teeth vary in number from two (Hydromys) to six (Rabbit) on each side of the two jaws. Four is the prevailing number outside the large division of the Rat-like Rodents. They are often set at an angle to the horizontal plane of the jaw, looking outwards and obliquely to its longitudinal axis; the individual teeth too are not unfrequently bowed in form, reminding us of those of Toxodon. This of course only occurs in those genera which have hypselodont teeth. The pattern of the teeth varies much, and the different forms recall the teeth of more than one other group of mammals. They are either bunodont or lophodont. In many cases the tooth is encircled with a ridge of enamel, which is either almost simple or has a more complicated contour; such teeth are by no means unsuggestive of the Toxodonts. Some of the lophodont molars are by no means unlike those of the Proboscidea. In Sciurus vulgaris the {461} encircling ridge is broken up into tubercles, which gives to the tooth a striking likeness to those of Ornithorhynchus. Other genera have teeth like those of many Ungulates. It has been shown by Sir J. Tomes[328] that the minute structure of the enamel differs in different groups of Rodents.
The skull shows certain primitive characters. In the first place there is no distinction between the orbital and the temporal fossa.[329] The sutures between the bones retain their distinctness for very long. Other characteristic features are the following:--The nasals are large, and so are the paroccipital processes. The palate in front of the molars is not distinct from the sides of the skull, its edge gradually becoming rounded off above. It is also very narrow. The premaxillae are large in relation to the great incisors. There is often a very much enlarged infra-orbital foramen through which passes a part of the masseter muscle. The jugal bone lies in the middle of the zygomatic arch, which is complete and enormously enlarged in the Spotted Cavy (Coelogenys paca). As in many Marsupials, the jugal bone sometimes extends backwards to the glenoid cavity, where the lower jaw articulates. It is usually said with an absolute want of accuracy that the cerebral hemispheres of the Rodents are smooth and without convolutions. This error has been repeated again and again in text-books. As a matter of fact the cerebral hemispheres of many forms are quite well convoluted,[330] the degree of furrowing corresponding, as in so many groups of mammals, with the size of the animal. This at any rate is generally true, though the large Beaver with its scant convolutions is an exception. The smaller forms, such as Mus, Sciurus, Dipus, and Cricetus are quite smooth-brained. The best furrowed brain of any Rodent which has been examined is that of the huge Hydrochoerus. The Sylvian fissure is very generally not pronounced; but is particularly well-marked in Lagostomus. In all, or in most, Rodents the hemispheres are separated by an interval from the cerebellum, the optic lobes being visible between the two.
The mouth cavity of this group of mammals is divided into two chambers by a hairy ingrowth behind the incisors; this arrangement is useful for animals which use their strong incisors {462} as gnawing and excavating tools as well as for the purposes of alimentation; for it allows of substances being gnawed away without the products of the chisel-like action being taken into the hinder cavity of the mouth. The Rodents have for the most part a simple stomach of normal form; but in a few this is complicated by a marked constriction, which divides the cardiac from the pyloric portions. The Hamster, for example, is thus characterised. In all the members of the order, with the exception of the Dormice and some allied forms, the caecum is large and often sacculated. In some forms (e.g. Arvicola, Myodes, Cuniculus) the large intestine is coiled upon itself in a spiral way--a state of affairs strongly suggestive of Ruminants.
The Rodents are primarily divisible into two great groups, the Simplicidentata and the Duplicidentata, characterised mainly by the upper incisor teeth. In the former there is but one pair of these teeth; in the latter a second smaller pair lie behind the former.
SUB-ORDER 1. SIMPLICIDENTATA.
SECTION 1. SCIUROMORPHA.
The Anomaluri are separated by Thomas and others from this section as an equal section, while by Tullberg they are grouped with Pedetes.
FAM. 1. ANOMALURIDAE.--The genus Anomalurus suggests at first sight the Flying Squirrels of Asia, Pteromys. It is, however, an entirely African genus, and is to be distinguished from the Asiatic Rodents by a series of scales at the root of the tail, imbricated, keeled, and forming possibly a "climbing organ." This character serves also to distinguish the present genus from Sciuropterus. The cartilage, moreover, which supports the patagium springs from the elbow. There are four molars in each half of each jaw. The eyes and ears are large. There are five fingers and toes, but the thumb is small, though provided with a nail. The sternum has seven joints, and nine ribs reach it. The clavicle is strong. Huet, who has recently monographed the genus,[331] allows six species. The species vary in size. {463}
Anomalurus peli appears, according to Mr. W. H. Adams,[332] to be a common species on the Gold Coast; it is coloured black and white, but in spite of the warning which this colour should convey, is considered by the perhaps rather omnivorous native as "the greatest delicacy." The animal is nocturnal, but affects only bright moonlight nights. Their "flying" consists of a jump from a high branch to a lower one, after which they reascend the tree to a point of vantage for another jump. They are said to feed upon nuts; but Tullberg only found the remains of leaves in the stomach.
Idiurus is a lately-described genus allied to Anomalurus. There are at any rate two species, I. zenkeri and I. macrotis. The thumb is more reduced than in Anomalurus, and the fibula, contrary to what is found in that genus and in most Sciuromorphs, is fused with the tibia below.
A third genus, very recently described and allied to both the foregoing, is Aethurus. It is a native of the French Congo,[333] and differs by the absence of flying membranes. It has, however, the pad of large scales. There is but one species, A. glirinus. It has a black bushy tail. The postorbital processes of the frontals are totally wanting--there are not even the traces to be seen in Anomalurus. The thumb has vanished. If we are to compare Anomalurus with the Squirrels then, thinks Mr. de Winton, the present genus is probably diurnal by reason of the want of flying membranes.
FAM. 2. SCIURIDAE.--The Squirrels, genus Sciurus, are world-wide in range, the Australian region and the island of Madagascar being alone excepted.
The eyes and the ears are large; the tail is of course long and bushy. The fore-feet have an inconspicuous thumb; the hind-feet have four toes. The soles of the fore-feet are naked or furry, those of the hind-feet are hairy. There are twelve or thirteen dorsal vertebrae, and in correspondence seven or six lumbars. The caudal vertebrae may be as many as twenty-five. In the skull the frontals are broad, and there are long {464} postorbital processes. The infra-orbital foramen is, as a rule, not large, but is increased in size in a few forms. The number of separate pieces of bone in the sternum is five. The molars of the upper jaw are five, but the first is very small and soon drops out.
The Squirrels are often rather brilliantly coloured. The Chinese Sc. castaneiventris has grey fur with a rich chestnut-coloured under surface. The Malabar Squirrel, Sc. maximus, as its name implies, a large animal, has a deep reddish or chestnut-coloured fur above, which becomes yellow below. The "Common Squirrel," "the lytill squerell full of besynesse," which is the Squirrel of this country, is brownish red on the upper parts and white below. It ranges from this country as far east as Japan. Like many other Rodents the Squirrel likes animal food and will eat both eggs and young birds. "Camel's hair" brushes are made from this animal. The genus Tamias, almost exclusively North American in range, is included by Dr. Forsyth Major[334] in this genus, which then consists of considerably over one hundred species.
The Ethiopian Ground Squirrels, genus Xerus, have a more elongated skull than Sciurus, and the postorbital processes are shorter. The feet are not hairy.
Nannosciurus forms a perfectly distinct genus of Squirrels. These "Pygmy Squirrels" differ in possessing a very elongated "face" and in the very broad frontal region. The teeth are unlike those of Sciurus in certain features, and have been especially compared by Forsyth Major to those of the Dormice. Four species of this genus are Malayan; one is West African.
The Bornean Rheithrosciurus macrotis is the only species of its genus. The genus may be distinguished by the exceedingly brachyodont molars, this feature being more marked in this genus than in all other Squirrels. It is called the "Groove-toothed Squirrel," from the "seven to ten minute parallel vertical grooves running down the front face of its incisors."[335]
The genus Spermophilus includes a large number (forty or so) of Palaearctic and Nearctic animals known as Sousliks. The ears are small; there are cheek pouches as in Tamias. The general aspect of the animal is like that of a Marmot, and they bridge over the exceedingly narrow gap which separates the Marmots from the true Squirrels. Anatomically the skull is like that of {465} Arctomys; the molars are five in the upper and four in the lower jaw. The caecum is relatively speaking very small; the measurements in a specimen of S. tredecimlineatus, dissected by Dr. Tullberg, were: small intestine, 580 mm.; large intestine, 170 mm.; and caecum, 27 mm. In Tamias also the caecum is not greatly developed. These animals are burrowing in habit.
The Prairie-dogs, genus Cynomys, of which the best-known species is perhaps C. ludovicianus, are very like the Squirrels, but they are not arboreal creatures; they live in burrows on the ground, as their vernacular name denotes. The genus is entirely North American, and four species have been differentiated.
The Prairie-dog or Prairie-marmot is some 10 inches to one foot in length. The tail is no more than 2 inches. The ears are very small; the thumb is fully developed and bears a claw. The measurements of the various sections of the intestine are the following:--Small intestine, 860 mm.; large intestine, 690 mm.; caecum, 75 mm. Thus the caecum is not large comparatively speaking. These animals dig burrows on grassy plains which they share with the Ground Owl (Speotyto cunicularis) and with Rattlesnakes, all three species appearing to live in perfect amity. Probably the Owls use the conveniently-constructed burrows, and the Rattlesnakes come there to look after the young of both.
FIG. 233.--Long-tailed Marmot. Arctomys caudatus. x 1/7.
Closely allied to the last are the Marmots, genus Arctomys. They differ in the rudimentary character of the thumb and in the longer tail. The eyes and ears are small. The distribution of the genus is Nearctic and Palaearctic. There are ten species of {466} the genus. The Alpine Marmot, A. marmotta, is familiar to most persons. The animal lives high up in the Alps, and when danger threatens it gives vent to a shrill whistle. It hibernates in the winter, and as many as ten to fifteen animals may be found closely packed together in a single, carefully-lined burrow.
The only other European species is A. bobac, the Siberian Marmot, which occurs in the extreme east of Europe, and is also Asiatic. There are four North American species, including the Quebec Marmot, A. monax.
FIG. 234.--Flying Squirrel. Pteromys alborufus. x 1/5.
The genus Pteromys (of which the proper name, antedating Pteromys by five years, appears to be Petaurista) is confined to the Oriental region, where there are a dozen species or so. The limbs are united by a parachute extending to the toes, and supported anteriorly by a cartilage attached to the wrists. There are also membranes anteriorly uniting the fore-limbs to the neck, and posteriorly uniting the hind-limbs to the root of the tail and a trifle beyond. The skull and the dental formula are as in Sciurus, but the pattern of the molars, which is much complicated, seems to argue a different mode of nutrition. There are twelve pairs of ribs. The large intestine (in P. petaurista) is very nearly as long as the small, and the caecum is also "colossal"; the measurements in an individual of the species named were: small intestine, 670 mm.; caecum, 320 mm.; large intestine, 650 mm. {467} The caecum is disposed in a spiral. The teats are three pairs, non-inguinal in position.
The size of these squirrels is 16 to 18 inches exclusive of the tail, which is longer. These animals can make an exceedingly long jump with the help of their flying membrane. Nearly eighty yards is the longest distance given for these aerial excursions. It is stated that they are able to steer themselves to some extent while in the air. As appears to be the case with so many Rodents, these animals feed largely upon beetles and other insects, besides bark, nuts, etc.
The allied genus Sciuropterus has a much wider range. It extends into the Palaearctic region and into North America, besides being found in India. There is here no membrane reaching to the tail. The palms and soles are furry. The caecum is very much shorter, and so is the large intestine. The latter, in S. volucella, is not more than one-third of the length of the small intestine. In other features there are no remarkable differences in structure, save that the mammae, always three pairs, may be inguinal.
Of the genus Eupetaurus[336] but a single species is known, which is limited to high altitudes at Gilgit and perhaps in Thibet. Its principal difference from the other genera of Flying Squirrels is that the molars are hypselodont instead of brachyodont. The interfemoral membrane is rudimentary or wanting. The one species is E. cinereus. It is thought to live "on rocks, perhaps among precipices." Dr. Tullberg attributes the hypselodont teeth to the fact that the mosses upon which it is believed to feed may have much sand and earth intermingled, which would naturally lead to a more rapid wearing away of the teeth, and hence a need for a good supply of dental tissue to meet this destruction.
FAM. 3. CASTORIDAE.--This, the third family of the Sciuromorpha, contains but one genus, Castor, the Beaver, with at most two species, one North American, the other European. This large Rodent has small eyes and ears, as befits an aquatic animal, and the tail is exceedingly broad and covered with scales; the transverse processes of the caudal vertebrae, in order better to support the thick tissues lying outside them, are divided in the middle of the series into two. The hind-feet are much larger than the fore-feet, and are more webbed than in any other aquatic Rodent. {468}
In the skull the infraorbital foramen is small as in Squirrels. The postorbital process has practically vanished. The four molars stand out laterally from the jaws. The incisors, as might be surmised from the habits, are particularly strong. The stomach has near the entrance of the oesophagus a glandular patch, which seems to be like that of the Wombat (see p. 144). In both sexes the cloaca is very distinct and comparatively deep.
The two species of the genus are C. canadensis and C. fiber. The latter is of course the European species, which is now found in several of the large rivers of Europe, such as the Danube and the Rhone. But it is everywhere getting scarce, and limited to quite small and isolated colonies.
In this country it is absolutely extinct and has been since before the historic period. There is apparently no documentary evidence of its survival down to this period. But the numerous names of places which are called from this animal illustrate its former prevalence. Examples of such names are Beverley in Yorkshire, and Barbourne or Beaverbourne in Worcestershire. In Wales, however, Beavers seem to have persisted longer. But they were rare in the Principality for a hundred years or so before the Norman Conquest. The king Howel Dda, who died in 948 A.D., fixed the price of a Beaver skin at 120 pence, the skins of Stag, Wolf, and Fox being worth only 8 pence apiece. The Beaver was called by the Welsh "Llost-llyddan," which means "broad-tail." Its existence in the country is handed down in the name of Llyn-ar-afange, which means Beaver lake. The last positive record of the Beaver in Wales seems to be the statement of Giraldus Cambrensis that in 1188 the animal was still to be found in the river Teivy in Cardiganshire. In Scotland the Beaver is said to have continued down to a later date. Ireland it never reached. The remains of this animal by their abundance show the former prevalence of C. fiber in this country. It is known from the fens of Cambridgeshire, and from superficial deposits elsewhere. The Thames formerly had its Beavers, and apparently it was widely spread through the country generally.
The Beaver not only furnishes collars and cuffs for coats; it was used, as every one knows, to provide hats. But the usefulness of the animal by no means ended here in the eyes of our {469} forefathers. The Rev. Edward Topsell observed that "for giving great ease unto the gowt the skinnes of beavers burned with drie oynions" are excellent. Castorein as a drug, if not in actual use, has quite recently been a part of the pharmacopoeia. It is derived from the anal glands common to this and other Rodents, and indeed many other mammals.
A large extinct form of Beaver is Trogontherium,[337] found in the "Forest-bed" of Cromer. The skull is about one-fourth longer than that of Castor. It has a less inflated bulla, and slightly more pronounced postorbital processes than Castor. The third molar (fourth grinding tooth) is relatively larger than in Castor, and has a rather more folded crown. The foramen magnum is more triangular.
FAM. 4. HAPLODONTIDAE.--A separate family seems to be required for the genus Haplodon, whose characters will therefore be merged with those of its family. It is to be distinguished from most other Squirrel-like creatures by the fact that there is no postorbital process to the frontal. The molar teeth are five in the upper and four in the lower jaw. The Sewellel, H. rufus, like the other species of the genus (H. major), is found in North America west of the Rocky Mountains. It has the habit of the Prairie-marmot, and has a short tail, only moderately long ears, and five-toed feet. Tullberg is of opinion that this animal nearly represents the ancestral form of the Squirrel tribe.
SECTION 2. MYOMORPHA.
This subdivision of the Rodents contains, according to Mr. Thomas's recent estimate,[338] no less than 102 genera. It is therefore obviously impossible to do more than refer to some of the more interesting of these. This group is again divided into the following families:--
(1) Gliridae, including the Dormice.
(2) Muridae, the Rats, Mice, Gerbilles, Australian Water-rats, Hamster.
(3) Bathyergidae, Cape Mole, etc.
(4) Spalacidae, Bamboo Rats. {470}
(5) Geomyidae, Pouched Rats.
(6) Heteromyidae, Kangaroo Rats.
(7) Dipodidae, Jerboas.
(8) Pedetidae.
The Gliridae have no caecum, so usual in the Rodentia. It is true that all the genera have not been dissected, but it is known that in the true Dormice, as well as in the genus Platacanthomys, a caecum is absent.
Apart from these few exceptions the Mouse-like Rodents all possess a caecum, though it is often not very large. They are all smallish animals, and are modified to a great variety of habit and habitat. There are burrowing, swimming, and climbing forms. The group is universal in range, even including the Australian region, in which they are the only Rodents.
FAM. 1. GLIRIDAE.--This family, also called Myoxidae,[339] includes the Dormice, and is entirely an Old-World family, absent only from the Malagasy region. Its most important differential character is the total absence of the caecum and of any sharp boundary between the small and large intestine. The molars are usually four. The eyes and ears are well developed.
The genus Muscardinus includes only the Common Dormouse, M. arellanarius. This small creature, 3 inches long with a tail of 2-1/2 inches, is, of course, a well-known inhabitant of this country. It is also found all over Europe. It is not particularly abundant in this country, and a good specimen is said to be worth half a guinea. As the specific name denotes, it lives largely on hazel nuts; but it will also suck eggs and devour insects. The animal makes a "nest" in the form of a hollow ball. Its hibernation is well known, and has also given rise to the German name ("Schlaefer") of the group. It was well known to Aristotle, who gave or adopted the name [Greek: Eleios] for the animal. Its winter sleep--suggestive of death--and its revivification in the spring gave the Bishop of Salamis, Epiphanius, an argument for the resurrection of man. The fur was reckoned in Pliny's time a remedy for paralysis and also for disease of the ears.
The genus Myoxus includes also but a single species, M. glis, the so-called "Fat Dormouse" of the Continent. It has no {471} glandular swelling at the base of the oesophagus, such as occurs in the last genus and in Graphiurus. Of Graphiurus there are thirteen species, all African in range. The genus does not differ widely from the last. There is, however, a glandular region of the oesophagus. Eliomys is the last genus of typical Dormice. It is Palaearctic in range.
Platacanthomys, of a Dormouse-like form, has like other Dormice a long tail, on which the long coarse hairs are arranged in two rows on opposite sides towards the tip; it is represented by a single species, P. lasiurus, from the Malabar coast. It is arboreal in habit. The fur is mingled with flattened spines. The molars are reduced to three on each side of each jaw. This form has been bandied about between the "Mice" and the "Dormice"; but Mr. Thomas's discovery of the absence of the caecum argues strongly in favour of its correct location among the Gliridae. Typhlomys is an allied genus, also from the Oriental region. This and the last are placed in a special sub-family of the Gliridae, Platacanthomyinae, by Mr. Thomas.
FAM. 2. MURIDAE.--This family, that of the Rats and Mice in a wide sense, is the most extensive family of Rodents. In it Mr. Thomas includes no less than seventy-six genera. The molars are generally three. The tail is fairly long, or very long, and the soles of the feet are naked.
SUB-FAM. 1. MURINAE.--The true Rats and Mice may be considered to form a sub-family, Murinae. The genus Mus, including the Rats and Mice in the limited sense of the word, contains about 130 species. They are exclusively Old World in range, being only absent from the Island of Madagascar. In the New World there are no species of the restricted genus Mus. The eyes and the ears are large; the pollex is rudimentary, and bears a nail instead of a claw. The tail is largely scaly. All the members of the genus are small animals, some quite minute. In this country there are five species[340] of the genus, viz. the Harvest Mouse, M. minutus, which has a body only 2-1/2 inches long with an equally long tail. It is the smallest of British quadrupeds with the exception of the Lesser Shrew. The Wood Mouse, M. sylvaticus, is about twice the size; it differs also from the last species in that it {472} frequents barns, and is thus sometimes mistaken for the Common Mouse, from which, however, it is to be distinguished by its coloration and longer ears. The latter, M. musculus, is too familiar to need much description. A curious variety of it has occurred. This has a thickened and a folded skin like that of a Rhinoceros, and the hair has disappeared. The Black Rat, M. rattus, is like a large Mouse, and is smaller and blacker in colour than the "Hanoverian Rat." It is sometimes called the "Old English Rat," but seems nevertheless to be not a truly indigenous Rodent. It has been so defeated by competition with the Hanoverian Rat that it is now not a common species in this country.
The Hanoverian or Brown Rat, M. decumanus, is a larger and a browner animal than the last. It is very widely distributed through the globe, no doubt largely on account of the fact that it is readily transported by man. The same is the case with the Common Mouse, whose real origin must be a matter of doubt. The original home of the Brown Eat is thought by Dr. Blanford to be Mongolia. There is so far a justification for the name "Hanoverian Rat" that the animal seems to have reached this country about the year 1728. But there is no reason for calling it, as is sometimes done, the Norway Rat.
Some members of this genus, whose fur is interspersed with spines, or which are quite spiny, have been separated as a genus, Leggada, which, however, is not generally allowed.
Closely allied again is Chiruromys, which has a strongly prehensile tail, a feature which is not common among the Myomorpha, though Dendromys, a tree-frequenting form, and Mus minutus, already spoken of, show the same character. Many Mice seem to have prehensile tails, which they can curl round branches; but it is not so fully developed as in the species just named.
A number of other genera are referable to the true Mice, the sub-family Murinae of Thomas's classification. The Syrian and African Acomys has very spiny fur, so much so that "when it has its spines erected it is almost indistinguishable at the first glance from a diminutive hedgehog." The genera Cricetomys, Malacomys, Lophuromys, Saccostomus, Dasymys are restricted to the Ethiopian region. Nesokia is Oriental, reaching {473} also the Palaearctic region. Vandeleuria, Chiropodomys, Batomys, Carpomys are Oriental, the last two being confined to the Philippines.
Another peculiar Philippine genus is Phlaeomys, of large size, and allied to it is Crateromys, originally confounded with it. Batomys granti is also confined to Luzon. Its molars are three, like those of the also restricted and Philippine Carpomys melanurus, which is an arboreal form. There is a second species, C. phaeurus.
Phlaeomys is placed, however, by Mr. Thomas in a distinct sub-family of its own, PHLAEOMYINAE, and is removed from the Murinae.
Hapalomys, with but one species, is Burmese. Pithecochirus is Javanese and Sumatran. Conilurus (also known as Hapalotis) is a genus containing species which are termed Jerboa Rats, on account of their mode of progression. They are desert and Australian forms. There are sixteen species.
FIG. 235.--Spiny Mouse. Acomys cahirinus. x 1/2.
Mastacomys, with one species, is limited to Tasmania. Uromys, with some eight species, is from Queensland, and inhabits also the Aru Islands and the Solomon Islands. The Celebesian Echiothrix, or Craurothrix as it should apparently properly be called, is another genus containing but a single species. Golunda is both Oriental and Ethiopian, one species occurring in each region. The beautiful little striped Barbary Mice, Arviacanthis (or Isomys), are African, north as well as tropical.
The genus Saccostomus resembles the Hamsters in the presence of cheek pouches. Its teeth, however, are Murine. It agrees with Steatomys in the comparatively short tail. The caecum is rather long. {474}
SUB-FAM. 2. HYDROMYINAE.--The genus Hydromys,[341] of which there are several species, the best known being H. chrysogaster, is an exclusively Australian form, and is aquatic in habit. It is a foot or so in length, and has a fairly long tail. The fore- and hind-limbs are webbed, in correspondence with its habits. The Australian Water-Rat is black, with an admixture of golden-coloured hairs dorsally and golden colour below, with a lighter median stripe. The thumb is small, and the webbing of the hands is not so marked as is that of the feet. The molars are only two in each half of each jaw. The caecum is rather small, the measurements of the alimentary canal being: small intestine, 895 mm.; large intestine, 278 mm.; caecum, 70 mm. Allied to the last is Xeromys, a genus which is also Australian, but limited to Queensland. It has been established by Mr. Thomas,[342] who discovered that it has the same reduced formula as Hydromys. Xeromys, however, is not an aquatic animal, and has unwebbed feet.
In the Luzon highlands Mr. Whitehead has discovered, and Mr. Thomas quite recently described,[343] a number of peculiar Rodents. Of these the genera Chrotomys, Celaenomys, and Crunomys are allied to the Australian and New Guinea Hydromys.
Chrotomys whiteheadi is unusual among Muridae, in its coloration being marked by a pale stripe down the back. The creature is the size of the Black Rat (Mus rattus). It is terrestrial not aquatic in habit, in spite of its likeness to Hydromys. The molars, however, are 3/3.
Crunomys fallax is more like Hydromys. It has, however, three molars, as in the last genus. But the skull has the flattened form characteristic of Hydromys as opposed to Mus.
Like Batomys, Celaenomys silaceus is also somewhat intermediate between Hydromys and Mus. It is described as very Shrew-like in appearance, and has a very pointed muzzle. Its habits Mr. Whitehead is "quite unable even to guess at." Like Hydromys and Xeromys this Rodent has but two molars.
SUB-FAM. 3. RHYNCHOMYINAE.--The genus Rhynchomys, containing but one species, Rh. soricioides (of Thomas), is also, as both its generic and specific names imply, a somewhat Shrew-like form in external aspect. The skull, too, is Insectivore-like in its {475} elongation, and the lower incisors are worn to needle-like points. The two molars are excessively minute, and thus the always large gap in the jaws is greatly exaggerated. It is suggested that this Rat is an insect-eater, but nothing positive is known.
SUB-FAM. 4. GERBILLINAE.--The Gerbilles form another sub-family, Gerbillinae, of the Muridae, or a family, according to some. The best-known genus is Gerbillus, including the Gerbilles proper. These animals are Old World in range, belonging to the three regions of that part of the world. There are a large number of species in the genus, over thirty. They have a Jerboa-like form, with rather long hind-limbs and a long and hairy tail. But the hind- as well as the fore-feet are five-toed. The molar teeth have no trace of tubercles, but only transverse lamellae of enamel. The incisors are orange; they are white in Dipus. Gerbillus pyramidum is 90 mm. long, with a tail of 125 mm. The ears are long, 13 mm. The tail has longer hairs at the tip.
FIG. 236.--Gerbille. Gerbillus aegyptius. x 1/2.
Psammomys is in some respects different. The tail is shorter than in Gerbillus; its length in an individual of 165 mm. was 130 mm. As in Gerbillus there are four pairs of teats, two pectoral and two inguinal. This genus is exclusively Palaearctic in range. Meriones has a range co-extensive with that of Gerbillus.
Pachyuromys is an Ethiopian genus with a short tail. As the generic name denotes, the tail is not only short but thick and fleshy.
SUB-FAM. 5. OTOMYINAE.--The allied genera, Otomys and Oreinomys, are Ethiopian. Otomys unisulcatus has a tail shorter than the body, the measurements of a female of this species being 137 mm. with a tail of 87 mm. The ear is long, whence the name; it measured in this specimen 20 mm. {476}
SUB-FAM. 6. DENDROMYINAE.--The genus Deomys is an African form, consisting of only one species from the Congo region. D. ferrugineus has a reddish colour as its name implies; the soles are quite naked and the tail is long and slender. It is considerably longer than the body, measuring (minus a fragment of the tip) 172 mm., while the body is 125 mm. long. The characters of the molar teeth, which are three, are intermediate in their form between those of the true Rats and those of the Hamsters.
Dendromys is also Ethiopian in range. There are several species. D. mesomelas is a smallish creature, 60 mm. long, with a tail of 90 mm.
Steatomys is another African genus, allied to the last. Its tail, however, is only half the length of the body. The two remaining genera are Malacothrix and Limacomys. Their range is African.
SUB-FAM. 7. LOPHIOMYINAE.--Allied to the Hamsters is the singular East African genus Lophiomys, with only one species, L. imhausi, of Milne-Edwards.[344] The size is between that of a Rabbit and of a Guinea-pig. The stomach is curved and somewhat intestiniform. It has been termed the Crested Rat on account of the "prominent crest of stiff hair running down the back." The fingers and toes are five, and the very long tail is clad with hair longer than that upon the body generally. The pollex is rudimentary, and the hallux is opposable.
The most remarkable structural feature in this genus concerns the skull, and on account of this it has been regarded as the type of a separate family. The temporal fossa behind the eye is covered over by a complete bony plate, formed by a downgrowth of the parietal, meeting an upgrowth from the malar; this singular arrangement of the bones recalls the conditions which obtain in turtles. The whole skull, moreover, is covered with symmetrically disposed granulations, such as are found in no other mammal; it suggests rather the skull of certain fish. It is believed that the bony plate already referred to is not really a portion of the bones of which it appears to be a prolongation, but merely an ossification of fasciae in this region. The atlas is granulated like the skull; there are sixteen pairs of ribs and a feeble clavicle. The molars are three, and of a peculiar form. {477} They have, in the case of the first three, transverse ridges, from which stand up two sharp and long tubercles. The other teeth have two ridges. The incisors are pale yellow. The shape of the teeth and the smallness of the caecum suggest that this Rodent is not so purely a vegetarian as others, and that it nourishes itself largely upon insects.
SUB-FAM. 8. MICROTINAE.--The Voles or Water-Rats form a distinct group of Murine animals, to which the sub-family name of Microtinae has been applied from the genus Microtus (more generally known as Arvicola), a genus which includes the Water-Rat and Field-Voles of this country. This genus has short ears, and a short and hairy tail. Its build is stouter and clumsier than that of the Rats. The genus is confined to the Palaearctic and the Nearctic regions. In this country there are three species. The best known is the Water-Vole or Water-Rat, M. amphibius, which has been seen by most people, and which frequents streams, ponds, and canals. The feet, curiously enough, are not webbed, which seems to argue the recent adoption of an aquatic life. Mr. Trevor-Battye has remarked that this animal, when swimming at leisure, uses its hind-limbs only, carrying the fore pair at the sides like a Seal. The Bank-Vole, M. glareolus, is rather a local species in this country. It is a terrestrial Vole, and burrows. The Field-Vole, M. agrestis, has become notorious on account of the "plagues," to which its immense numbers have on occasions given rise. It is the smallest species, and has a greyish-brown fur like the Water-Vole, the Bank-Vole being redder. To give an idea of the cost of the depredations of this animal, Mr. Scherren quotes[345] a farmer who gave evidence before the Agricultural Commission to the effect that, putting the damage of one Vole at two pence, the amount of loss suffered on a farm of 6500 acres in two years would be L50,000!
The genus Fiber comes very near the last. It is a North American genus. The hind-feet are slightly webbed; the tail is a trifle shorter than the body, and is compressed and scaly, with scattered hairs. The thumb is short, but with a fully-developed claw. As in the last genus, the small and large intestines are roughly of the same length, and the caecum is about one-fourth of the length of either. It is known as the "Musquash." {478}
Of Fiber zibethicus, or rather a closely-allied form, F. osoyoosensis, from Lake Osoyoos near the Rockies, Mr. Lord writes[346] that it constructs for itself a house of bulrushes built up from the bottom in 3 or 4 feet of water. It is dome-shaped, and rises about a foot out of the water. "If a dead or badly-wounded duck be left on the pool, it is at once seized on, towed into the house, and doomed." Thus it appears that this Rodent, like so many others, is largely carnivorous. It has also been asserted that it eats fish.
Neofiber is an allied genus, North American in range. The species, N. alleni, is compared, as regards outward form, with the Water-Vole, M. amphibius. It has, however, a shorter tail.
Another very well-known member of this sub-family is the Lemming. The name, however, applies to two quite distinct genera. The genus Cuniculus, including the Banded Lemming, C. torquatus, is an inhabitant of North America, Siberia, and Greenland. The tail is short, its length being 12 mm. as against a body length of 101 mm. The feet are furred beneath, a not unusual state of affairs in Arctic mammals. The ears are very slight. The thumb is well developed, and bears a claw.
In Myodes, on the other hand, which is not so markedly an Arctic animal, though occurring in both Palaearctic and Nearctic regions, the ears are rather bigger, though still smaller than those of Microtus. The under surfaces of the feet are similarly furred. The tail is also short. It is commonly said that the two genera are to be distinguished by the furred feet of Cuniculus, and by the absence of fur in the present genus. That, according to Tullberg, does not appear to be the case. The differences are thus so much reduced that it seems almost unnecessary to retain the two genera. The best known species of Myodes is of course the Scandinavian Lemming, M. lemmus. This animal used to occur in this country in Pleistocene times (as did also C. torquatus), and recently Dr. Gadow has found remains with skins attached in caves in Portugal. It may still survive in the mountains of the Peninsula.
The actual habitat of the Lemming in Scandinavia is the great tablelands, 3000 feet high in the centre. The migrations do not take place with regularity; even twenty years may elapse before the appearance in cultivated lands of those countless {479} hordes so familiar (as far as their description is concerned) to everybody. The Lemmings do not return from their exodus. They die from various causes, including combats with one another. Their chief foes, however, are Wolves and Gluttons, Buzzards and Ravens, Owls and Skuas, which batten on the migrant hordes. Their sudden increase in numbers recalls the similar increase at times of the Field-Vole, to which reference has already been made.
Ellobius is an Old-World genus, which leads a "Talpine" life, and has in consequence rudimentary external ears and very small eyes. The tail is short. Contrary to what might be expected from its mode of life, the claws upon the digits are not strong.
The remaining genera of Vole-like Murines are Phenacomys and Synaptomys from North America, and Siphneus from Palaearctic Asia. Evotomys is one of those genera which are common to both the Palaearctic and the Nearctic regions, but the bulk of the species are North American.
SUB-FAM. 9. SIGMODONTINAE.--This is the name given to another sub-family of Murine Rodents, a group which includes the Hamsters in the Old World as well as a large number of South American genera of Rat-like animals. Of these latter there are a very large number, the bulk of the group being American.
The Hamsters, genus Cricetus, as it is usually called, although apparently the correct name is Hamster, are Old-World forms of Pouched Rats. The Common Hamster, C. frumentarius, is about 210 mm. long, with a tail of 58 mm. It has cheek pouches. The small and the large intestines are not very unequal in length, and the caecum is fairly large, being about one-sixth to one-seventh of the length of either. It is a purely vegetable-feeding creature, and in Germany where it occurs (and from which language its vernacular name is derived), hibernates during the winter in its burrow, having previously surrounded itself with a great accumulation of food carried thither.
To North America are peculiar the genera Onychomys, Sigmodon, and Peromyscus. The genus Sigmodon, the Cotton Rats, reaches Central America, and even gets a little farther south. The other two genera, though mainly North American, also extend their range to the south. Onychomys has hairy {480} foot-pads, a state of affairs which characterises a number of these Rodents.
The genera Megalomys, Chilomys, Reithrodontomys, Eligmodontia, Nectomys, Rhipidomys, Tylomys, Holochilus, Reithrodon, Phyllotis, Scapteromys, Acodon, Oxymycterus, Ichthyomys, Blarinomys, Notiomys are South American forms. Oryzomys and Rheithrodontomys are common to both parts of the New World.
The genus Ichthyomys is remarkable on account of its un-Rodent-like habits and of certain associated structural changes. I. stolzmanni was obtained from Mount Chanchamays in Peru at an altitude of 3000 feet; it is a habitual fish-eater, and lives in streams. Another species, I. hydrobates, was formerly referred to Habrothrix. The skull shows likenesses to that of the Australian Hydromys; but the most marked characters of adaptation are those of the teeth and caecum. The cutting edges of the upper incisors form a reversed [347] of obvious use in holding a slippery fish. The caecum is much reduced, short, and narrow. The general Otter-like shape of the creature is largely due to its flattened head, though its "size and general proportions are much as in the common Black Rat."[348]
This sub-family contains a number of genera from Madagascar, viz. Brachytarsomys, Nesomys, Hallomys, Brachyuromys, Hypogeomys, Gymnuromys, and Eliurus.
SUB-FAM. 10. NEOTOMINAE.--The last sub-family of the Muridae is that of the Neotominae, containing the North American genera Neotoma, Xenomys, Hodomys, and Nelsonia.
FAM. 3. BATHYERGIDAE.--This family contains several genera which consist of subterranean forms. All these Rodents agree in a number of characters, of which the principal are as follows:--
The eyes are very small, and the external ears are reduced to the merest fringe of skin round the aural aperture. The legs are short, as is the tail; the hair-covering is reduced--a reduction which finds its culmination in the nearly nude Heterocephalus. Being burrowing creatures, a number of other modifications in accordance with this mode of life are to be seen in their structure. The upper incisors stand out in front of the closed lips, and prevent the entrance of earth. For the same reason {481} the nostrils are small, and the forehead but little expanded between them.
The genus Bathyergus contains but a single species, the Cape Mole-Rat, which is found in Southern Africa; it is of moderate size, not exceeding a small Rabbit in dimensions. On the fore-limbs are exceedingly long claws, of which that borne by the second finger is the longest, and the claw of the thumb the shortest. The hind-feet have by no means such long claws. The scratching and burrowing is naturally chiefly effected by the fore-limbs. The small and large intestines are of equal length, and each is rather more than six times the length of the caecum; in these measurements the present genus differs from the next.
Georhychus.--Of this African genus there are about ten species. The claws are not so long as in the last genus, but there are, as in Bathyergus, four molar teeth on each half of each jaw. The intestinal measurements in an example of G. capensis were: small intestine, 25 inches; caecum, 4 inches; large intestine, 15 inches.
The genus Myoscalops or Heliphohius (also with an African range) has six back teeth on each side. A number of species sometimes referred to the last genus are placed here by Mr. Thomas. The claws are small.
One of the most remarkable genera of this family is the little Heterocephalus from Abyssinia and Somaliland. As Mr. Thomas justly remarks,[349] it "is a peculiar-looking little creature, about the size of the Common Mouse, but looking almost more like a tiny hairless puppy on account of its nearly naked skin, small eyes, and peculiar physiognomy." Though apparently naked, there are numerous scattered hairs over the entire body, and the toes are fringed with stiffish hairs, which must be advantageous to a burrowing animal. There are two species, H. glaber (originally described by Rueppell), and H. phillipsii, of which our knowledge is due to Mr. Thomas. The length of the entire creature including the tail is not more than 134 mm., both species being approximately of the same dimensions. Mr. Lort Phillips, the discoverer of the species which bears his name, writes "that this little creature, called 'Farumfer' by the Somali, throws up in places groups of miniature craters, which exactly resemble volcanoes in active eruption. When the little beasts were at {482} work, I used frequently to watch them, and found that the loose earth from their excavations was brought to the bottom of the crater, and sent with great force into the air in a succession of rapid jerks, and that they themselves never ventured forth from the shelter of the burrows."[350]
FAM. 4. SPALACIDAE.--"The Spalacidae," observes Dr. Blanford, "are sometimes called rodent moles, and resemble a mole in general aspect, having cylindrical bodies, short limbs, small eyes and ears, large claws, and a short or rudimentary tail." The existence of a spiral valve in the caecum may perhaps characterise this family; but it has at present only been found in the two genera Spalax and Rhizomys.
Spalax has inconspicuous eyes and external ears. The tail is totally absent. The lower incisors are more developed than in other Rodents; they project in a bony sheath beyond the posterior end of the ramus of the lower jaw. The scapula is long and narrow. The large intestine is half the length of the small intestine. The animal seems to have only two pairs of teats, one pectoral the other inguinal.
Spalax typhlus of Egypt, which is probably not different from the European form, makes extensive burrows, some of the branches being even 30 to 40 yards in length. In a "domical chamber," situated along the course of one of these burrows, Dr. Anderson found no less than 68 bulbs stored up. Its eyes are mere black specks among the muscles, but they appear, however, to have a proper organisation. There are altogether eight species of the genus, which is entirely Palaearctic in its range.
The genus Rhizomys, including a number of species known as Bamboo Rats, is purely Oriental in range. Rh. sumatrensis reaches a length of 19 inches; the better-known species, Rh. badius, is at most only 9 inches in length--in both cases the measurements are exclusive of the tail, which is a quarter to one-third of the length of the body, and is not scaly but nearly naked, with a few scattered hairs. The molars are three, and the incisors usually orange in colour; but sometimes the upper incisors are white as in Rh. badius. There are thirteen dorsal vertebrae. In Rh. pruinosus the large intestine is considerably longer than the small intestine; the lengths of the two sections of the gut are 42 and 30 inches respectively. In another {483} species the large intestine is slightly shorter than the small intestine. In Rh. badius the two parts of the gut are almost exactly equal in length. There are three pairs of inguinal and two pairs of pectoral teats. The name Rhizomys appears to have been given to the animals of this genus for the reason that they feed largely on roots. They burrow, and, like many other burrowing animals, feed in the evening. As is the case with other forms, Rhizomys is said to burrow with the assistance of its teeth as well as of its claws.
FIG. 237.--Bamboo Rat. Rhizomys badius. x 1/4.
Tachyoryctes is an African genus closely allied to the last. There are three Ethiopian species. It is mainly to be distinguished by the different pattern upon the grinding surface of the molars.
FAM. 5. GEOMYIDAE.--This family of burrowing Rodents is limited to North and Central America. The animals have cheek pouches, and small eyes and ears, in accordance with their mode of life. The claws of the fore-limbs are very strongly developed.
The genus Geomys contains some eight species, which are Central and North American, not extending, however, far north. The incisors of the upper jaw are grooved with two grooves. There are three pairs of teats--one axillary, and the two remaining inguinal.
Thomomys, without grooves on the incisors, reaches to Canada in the north, and does not extend as far south as the last genus. {484}
Allied to this family, and indeed united with it by Tullberg, but kept separate by Thomas, is the
FAM. 6. HETEROMYIDAE.--The members of this family are also American, but are not confined to the northern-central regions of that continent, for the genus Heteromys extends into South America.
The genus Dipodomys, with twelve species, is of a Jerboa-like form, as the following measurements of an example of D. merriami will show. The length of the head and body was 85 mm.; of the tail 127 mm.; the hind-foot is 32 mm. It has but four toes. The hind-limb is longer than the front-limbs.
In Perodipus the same form is exhibited. There are, however, five toes, and the sole of the foot is hairy. The axis vertebra and the two following vertebrae are fused together.
Perognathus is a third genus. It has the same general slender form, but the tail is not so long, being but little longer than the body. The hind-limbs, too, are shorter. The teats of this and of Perodipus are as in Geomys. The two remaining genera of the family are Heteromys and Microdipodops.
FIG. 238.--Jerboa. Dipus hirtipes. x 1/3. Eastern Europe.
FAM. 7. DIPODIDAE.--This family consists of small, plain-living, and leaping or arboreal creatures, commonly known as Jerboas. The main anatomical characters of the family are the following:--There is a large infra-orbital foramen. The molars are always reduced, the premolar being either absent in the lower jaw alone or in both jaws. This family presents an obvious likeness to Dipodomys (hence the name of the latter) and to some other members of the American family Heteromyidae {485} There is even the same ankylosis of the neck vertebrae. We find, moreover, the same association of long-legged and shorter-legged forms that characterises the Heteromyidae.
FIG. 239.--Bones of right pes of Jerboa, Dipus aegyptius. x 3/4. a, Astragalus; c, calcaneum; c^2, middle cuneiform; c^3, outer cuneiform; cb, cuboid; n, navicular; I-IV, first to fourth toes. (From Flower's Osteology.)
The typical genus Dipus is a smallish quadruped with long naked ears and a long tail. The ten species are all Palaearctic in range. The fore-limbs are short and five fingered, and the short pollex has no claw; the hind-limbs are excessively long and only three-toed. The bony structure of these limbs is remarkable. The three metatarsals are elongated almost like those of a bird, and are ankylosed together. The digits have long phalanges which alone reach the ground as the animal hops. It is a curious fact, and one not so easily identifiable with the way of life, that the neck vertebrae of this genus are ankylosed together with the exception of the atlas, which is free; the arrangement is precisely like that of the Sperm Whale. The last vertebra is, however, sometimes free. The Jerboas not only leap but they burrow, and their strong incisors are said to be used in burrowing through stony ground. They are eaten by the Arabs, and are, or have been, called Daman Israel, i.e. Lamb of Israel. In D. hirtipes the body and tail measure respectively 4-1/2 and 7 inches. The hind-feet have a tuft of long hairs below. Mr. W. L. Sclater's newly-founded genus Euchoreutes[351] is somewhat more primitive in its characters than is Dipus. The general form is the same, with long ears and a long tail. But there are five toes to the hind-limb, the two lateral ones though nailed being much shorter than the middle three. It has a "long pig-like snout," and the tail is cylindrical as in most other Jerboas, with a tuft of longer hairs at the end. The incisor teeth, grooved in Dipus, are here smooth, as in Alactaga. The species was probably obtained "in the sandy plains round the city of Yarkand." {486}
Alactaga is much like Euchoreutes; it has five toes, a cylindrical tufted tail, the hairs at the end distichous, smooth incisors, and a premolar present in the upper jaw. It also differs from Euchoreutes by the much smaller auditory bulla as well as in the fact that the infra-orbital foramen has no separate passage for the nerve, which passage is to be distinguished in both Dipus and Euchoreutes. The best-known species is the Siberian Jumping Rabbit, A. jaculus. Beneath the ends of the three main toes of the feet are remarkable fan-shaped pads. In A. decumana the body and tail measure 7 and 10 inches respectively, the ears 2 inches. Platycercomys, a fourth genus of the family, is much less known and is to be differentiated from the last three genera by the fact that it has no premolars at all, the grinding tooth formula being thus 3/3. The tail too is flattened and "lancet shaped." It extends from Siberia to Nubia, and thus just enters the Ethiopian region.
The above are the more typical Jerboas. There remain several forms which are not at all Jerboa-like in their way of life, but are nevertheless, on anatomical grounds, placed with them. Zapus, an American genus, with the exception of one Palaearctic species, is transitional in that its hind-legs are rather long, but there is not so much difference between them as in the typical Dipodidae. Sminthus is at the opposite extreme to Dipus. Its feet are short and of equal length; it climbs in trees, and may perhaps be looked upon as nearest of all Dipodidae to the ancestral form of the group.
FAM. 8. PEDETIDAE.--The genus Pedetes contains but one species, P. caffer, the Cape Jumping Hare. The animal suggests a large Jerboa in appearance on account of its jumping habits, the long hind-limbs, and the long tail. The length of a fair-sized example is some 17 inches, with a tail of the same length. The eyes and ears are large. The hands are five-fingered and the feet only four-toed, the hallux being of course the absent digit. In the skeleton it is interesting to note that the second and third cervical vertebrae are so close together that there can be no free movement; interesting because in Dipus the cervicals are actually ankylosed. The dorsal vertebrae are twelve. The small intestine is long, measuring 7 feet 4 inches, while the caecum is short, being only 8 inches long. The large intestine is 3 feet 10 inches long. The gall-bladder appears to be {487} absent,[352] an exceptional state of affairs in Rodents. A singular fact in the anatomy of this animal is the existence of a septum dividing the lower part of the trachea. This is sometimes met with in birds. As might be supposed from its large eyes, the Spring Haas, as the animal is sometimes called, is nocturnal. Its long hind-limbs permit it to leap enormous distances. It is a burrowing Rodent.
SECTION 3. HYSTRICOMORPHA.
FAM. 1. OCTODONTIDAE.--The Rodents of this family are of small to moderate size, the only, relatively speaking, giant in the family being the "Water-Rat," Myocastor. The toes are with but one exception not reduced; the tail is long in the majority of the genera. The teats are placed high up on the sides of the body. The clavicle is fully ossified. All the genera are South or Central American in range with the exception of Petromys.[353]
SUB-FAM. 1. OCTODONTINAE.--Octodon has four species, which are all Chilian, Peruvian, and Bolivian in distribution. The Degu, O. degus, has a length of 160 mm., with a tail 105 mm. long. The ears are 18 mm. long. At the roots of the claws are longish and stiff hairs which appear to serve as "combs." The tail has long but sparsely scattered hairs. There are twelve pairs of ribs. The lengths of the various sections of the intestine are as follows: small intestine, 680 mm.; caecum, 90 mm.; large intestine, 390 mm. These animals live in large companies. Closely allied is the genus Habrocoma (more correctly, as it appears, to be written Abrocoma), with two species. H. bennetti is 204 mm. long, with a tail of 103 mm. The ears are long, 22 mm. The fore-feet have no outward trace of the thumb. Stiff hairs like those that characterise Octodon are found also in this genus. The fur is very soft. The furring of the tail is much thicker than in Octodon.
Spalacopus with but a single species, S. poeppigi, is a burrowing animal, from which indeed, and on account of its resemblance to Spalax, it has received its name. The ears in accordance with the underground life are short, only 5 mm. in length in an {488} example of 120 mm. The tail too is reduced, being in the same example only 42 mm. in length. As in the last two genera the large intestine is about one half of the length of the small intestine.
The "Tuco-tuco," genus Ctenomys, has also short ears and tail. The claws of the fore-feet are longer than those of the hind-feet.
A related form is Aconaemys (better known as Schizodon), with similar external characters; it inhabits high localities on the Andes.
Petromys is the only genus of the sub-family which is not American in habitat. It is an African form and there is but one species. Its anatomy conforms to that of the genera already considered. The main difference in structure is shown by the teeth. Their surface is uneven, and differs from that of other Hystricomorphs "in that the enamel to the inside of each upper jaw-tooth and outside on each lower jaw-tooth forms two tubercles, to which correspond grooves in the reverse position of the applied teeth."
SUB-FAM. 2. LONCHERINAE.--The genus Echinomys with thirteen species belongs to the Neotropical region. The members of the genus are entitled "Spiny Rats" since they have spines mixed with the fur. The tail is long and the ears are very well developed. Both feet are five-toed. The tail is scaly as well as haired. Trichomys (also called Nelomys) is very close to the above, and is also from the same part of the world.
The genus Cannabateomys contains but one species, C. amblyonyx, which was formerly included in the genus Dactylomys, but has lately been separated by Dr. Jentink.[354] The animal is Brazilian and has a total length of 520 mm., of which 320 mm. belong to the tail. It is a climbing rat, and in accordance with that way of life has undergone some modifications. The fore-feet are four-toed, the two middle toes being markedly longer than the outer ones. The hind-feet are five-toed with the same greater development of the two middle toes. The claws are small and somewhat nail-like.
Dactylomys, also Brazilian, and with but one species, D. dactylinus, differs from the last in the fact that the molars are simpler in form; they are divided into two lobes, each of which {489} has but a single enamel fold, whereas in Cannabateomys these teeth have several enamel folds. The tail, moreover, is but slightly hairy.
Loncheres with eighteen species is another Neotropical genus allied to the foregoing. Small spines are, as in many of these genera, intermingled with the fur. This genus has as many as seventeen dorsal vertebrae, which is an unusually large number. L. guianae is known as the "Porcupine Rat." Allied genera, also South American, and without spines in their fur, are Mesomys, Cercomys, and Carterodon.
The South American Thrinacodus is also known by one species,[355] T. albicauda, which has rather more than the distal half of the long tail of a white colour. The fore-feet have four toes. The ears are broad and short.
SUB-FAM. 3. CAPROMYINAE.--A third sub-family of the Octodontidae is formed by the genera Myocastor, Capromys, Plagiodontia, and Thrynomys, which are all Neotropical forms with the exception of the last, which is African.
Thrynomys (better known perhaps as Aulacodus) is a genus of African Rodent, containing some four species. The best-known of these is T. swindernianus, the Ground-Rat of West and South Africa. Its structure has been investigated by Garrod,[356] by Tullberg,[357] and by myself.[358] The fur is mingled with flattish bristles; the tail is moderately long, about half as long as the body. The fore-feet are five-toed, but the two toes at each end of the series are quite small. The hind-feet are only four-toed, the hallux being absent. The claws of the hind-feet are stronger than those of the fore-feet. The ears are not long. The limbs are decidedly short, hence the name of "Ground-Pig" sometimes applied to this animal. The molars are four in number in both jaws. The incisors of the upper jaw are twice grooved. There are thirteen dorsal vertebrae. The length of the small intestine is 60-1/2 inches, that of the large 49; the caecum is short, being only 8 inches long. It is a remarkable fact that the acromion is joined to the rest of the spine of the scapula by a joint.
Myocastor, a name which seems to have the rights of priority over the more familiar Myopotamus, applies to a large South American aquatic Rodent. The general aspect of the animal {490} suggests a Water-Rat of large size (it has been exhibited in shows as a phenomenal product of London sewers!); the tail is nearly as long as the body. The ears are small. The limbs are short. The tail is naked. The hind-feet are webbed, but not so much so as in Hydromys. A small thumb is present. The animal has thirteen pairs of ribs; the molars are four in each jaw. The large intestine is more than three times the length of the small, and the caecum is, as in the last genus, relatively short.
Capromys is a genus[359] which is remarkable on account of its restricted distribution. It is found only in the islands of Cuba and Jamaica. There are four species, of which C. melanurus is a dark brown-coloured animal with a blacker tail, nearly as large as a Rabbit. The native name of this Rodent is "hutia." It is also remarkable for having a stomach more complicated than is the rule among the mammals of this group. The organ is divided by two constrictions into three compartments. In C. pilorides the liver is occasionally divided up in an extraordinary fashion into small lobules. Capromys has the large number of sixteen dorsal vertebrae.
FAM. 2. CTENODACTYLIDAE.--For these African genera it seems admissible to form a distinct family, though Thomas, and Flower and Lydekker, only allow to the genera Ctenodactylus, Pectinator, and Massoutiera sub-family rank. On the other hand, Tullberg removed these genera entirely from the Hystricomorph section and placed them as a section of the sub-tribe Myomorphi of the tribe Sciurognathi. It was chiefly the form of the mandible which led to this placing, for in these Rodents, as in all Squirrel- and Rat-like Rodents, and unlike what is found in the Hystriciform genera, the angular process of the mandible is not bent sideways.
The genus Ctenodactylus derives its name from the peculiar strong bristles which form a comb-like structure upon the hind-feet and hide the claws; these are stated to be for the purpose of dressing the fur. The Gundi of North Africa, C. gundi, has a length of 190 mm., with a short tail of 17 mm. The ears are only moderate in size. The dental formula of the molars is 4/3. The incisors are white. The feet have four digits, and the hind-limbs are the longer. The large intestine is distinctly longer than the small intestine. {491}
Pectinator spekii is the only representative of a genus not far removed from Ctenodactylus; it is a smallish Rodent, 6 inches in length, exclusive of a rather bushy tail nearly 3 inches long. It comes from Abyssinia. It has somewhat the appearance of a Squirrel, which is heightened by the fact that when sitting the tail is arched over the back; when running the tail is carried out straight. There are only four toes visible externally on both fore- and hind-limbs, but pollex and hallux exist in the skeleton, with a single phalanx each. There is only a single pair of mammae, and in correspondence with this but two or three young are produced at a time. The hind-feet have bristles very much like those of Ctenodactylus. The molars, however, are 4/4. There are twelve ribs, of which six reach the sternum. The latter is made up of six pieces, and the manubrium in its breadth anteriorly suggests that of the Vizcachas. The clavicles are present.[360]
FIG. 240.--Carpincho. Hydrochoerus capybara. x 1/12.
FAM. 3. CAVIIDAE.--This family, which includes the Cavies and the Capybara, is entirely South American and West Indian in distribution. It embraces animals of fair to large size, the Capybara {492} (or Carpincho) being the greatest of existing Rodents. The ears are well developed. The toes are commonly reduced, and the members of this family possess only a rudimentary tail. The hair though rough is not spiny. Other characters had best be deferred until the several genera are treated of. We shall begin with the giant of the family, the genus Hydrochoerus. This genus contains but a single species, H. capybara of South America. It reaches a length of some 4 or 5 feet. The ears are not large; the tail is completely absent. The fore-feet are four-toed, the hind-feet three-toed; the digits are webbed, though not to a very great degree, and the nails have the appearance of hoofs. There are fourteen dorsal vertebrae; the clavicle is absent. In the skull the paroccipital processes are of great length. The infra-orbital foramen is large. The most remarkable fact about the teeth is the great size of the posterior molar of the upper jaw; it has fourteen folds of enamel, more than all the anterior teeth possess collectively. The incisors are white and grooved in front. The measurements of the alimentary tract as given by Tullberg are: small intestine, 4350 mm.; caecum, 450 mm.; large intestine, 1500 mm.
FIG. 241.--Patagonian Cavy. Dolichotis patachonica. x 1/10.
The Capybara or Carpincho is largely aquatic in its habits. Their "favourite locality," writes Mr. Aplin,[361] "is a broad laguna {493} in the river, furnished with open water, and also beds of 'camelotes,'--a sloping open grassy bank on one side, where the Carpinchos can lie in the daytime in the cooler weather, sleeping and basking in the sunshine; on the other a low shelving bank, clothed with 'Sarandi' scrub growing out into the black reeking mud and shallow water beyond." They always take to the water when alarmed, at a rate and with a gait which reminded Mr. Aplin of a Pig. When in the water they swim slowly with the upper part of the head, including nose, eyes, and ears, above the surface. But they can dive for a considerable time and distance, and baffle their enemies by seeking the shelter of a mass of water-plants, and lying there with their noses only just above the surface.
The genus Dolichotis[362] has long ears, and generally resembles a rather long-legged Hare in appearance. The front-feet are four-toed, the hind three-toed. The Patagonian Cavy, as this animal is called, has twelve dorsal vertebrae, and rudimentary clavicles.[363] The paroccipital processes are long; the incisors are white, and are not grooved in front. The sternum has six pieces, and seven ribs reach it.
Cavia, including the species C. porcellus, the Guinea-pig (which name is a corruption apparently of Guiana pig), has the same number of toes on its hind- and fore-feet as has the Capybara. The name applied to the wild stock whence our Guinea-pig is derived is the Restless Cavy. The fur is greyish; of the domestic animals the colour is too well known to need description.
FAM. 4. DASYPROCTIDAE.--The genus Coelogenys includes but two species. C. paca, known as the "Spotted Cavy" or "Paca," has a brown body, with white spots like those of a Dasyure; it is one of the largest of Rodents, and has a quite short tail. The hand and foot are both provided with five digits; but the thumb is small, and in the foot the three middle toes considerably exceed the others in length. The hind-foot is practically three-toed. The fibula is not nearly so reduced as in Dolichotis. The skull of the animal is remarkable for the extraordinary development in breadth of the jugal arch, which is sculptured externally. There is a large cavity formed below, at the maxillary end of this huge {494} arch, by the curving inwards of the bone, which lodges a cavity continuous with the mouth. The palate has anteriorly a ridge on either side, and is thus divided from the sides of the face in a way which is not found[364] in the allies of Coelogenys. Clavicles are present. There are thirteen dorsal vertebrae. The incisors are coloured red in front. The animal is South American, and in that continent is limited to the Brazilian sub-region. This, the best-known species of Paca, is called the Gualilla by the natives of Ecuador; in the same district another form is met with which the natives term Sachacui (signifying Forest Cavy). It is very often the case that a different native name expresses a real specific difference; and to the latter form M. T. Stolzmann has given the name of C. taczanowskii.[365] This form, unlike the common Paca, which is fond of forests and low-lying ground in the neighbourhood of water, is alpine in habitat, living upon mountains of 6000 to 10,000 feet. It burrows in much the same way as its congener, and is greatly sought after as food, its meat possessing an "exquisite taste." It is pursued by dogs, by whose aid one of the two entrances to the burrow is guarded, and the creature is smoked out and killed with a stick.
The genus Dasyprocta, containing those Rodents known as Agoutis, is divisible into several species, apparently about twelve, all of which are, like the Pacas, confined to the Neotropical region. They have, however, a much wider range within that region, and occur as far north as in Central America and in some of the West Indian Islands. They are of rather smaller size than the Paca, and are without spots. The colour is of a golden brown in some forms, but usually has a freckled, grizzled, greenish kind of appearance. The tail is stumpy, the hind-limbs are distinctly longer than those of the Paca, and the two lateral toes have disappeared from the feet--a concomitant as it seems of the Agouti's greater powers of running. The three metatarsals are closely pressed together, and the foot is as it were on the way towards the highly-modified foot of the Jerboa. The fore-feet are, however, five-toed. The clavicle is rudimentary,[366] whereas it is well developed in the Paca. The skull has not the peculiar modifications of that of the last-mentioned type. The sternum has seven {495} pieces, and eight ribs reach it. A curious difference between this genus and the last is in the relative proportions of the regions of the intestine. The figures given by Tullberg for the two animals are--for Coelogenys, small intestine, 4800 mm.; caecum, 230 mm.; large intestine, 21,000 mm.;--for Dasyprocta aguti the same author gives: small intestine, 4200 mm.; caecum, 200 mm.; large intestine, 1000 mm. The Agouti, says Mr. Rodway,[367] is as wily as the Fox. "If chased he will run along the shallows of a creek to hide his scent from the dogs, or swim over and back again several times for the same purpose. He never runs straight when pursued, but doubles, often hiding until a dog has passed, and then making off in a different direction. Like the fox he has been hunted for a very long period, and, like Reynard, has grown wiser with every generation."
FIG. 242.--Agouti. Dasyprocta aguti. x 1/10.
FAM. 5. DINOMYIDAE.--The genus Dinomys of Dr. Peters[368] is a very little known and remarkable form from South America allied to the Capybara, the Chinchilla, and other South American Rodents. It is only known by a single example found wandering about a courtyard in a town of Peru. It is externally like, and of about the same size as the Paca, but has a hairy tail. The animal is four-toed and plantigrade; the ears are short, and the nostrils are [369]-shaped. It is usually regarded as belonging {496} to a separate family which will include but the one species, D. branickii.
FAM. 6. CHINCHILLIDAE.--This family, likewise South American, contains three genera,[370] all of which agree in having long limbs, especially the hind-limbs, and a bushy and well-developed tail. The hair is exceedingly soft, hence the commercial value of "chinchilla."
The genus Chinchilla, containing but a single species, C. laniger, is a small and squirrel-like creature, living at considerable heights in the Andes. The eyes, as it is a nocturnal creature, are naturally large; and so also are the ears. The fore-feet have five toes, the hind-feet only four; they are furnished with feeble nails. The innermost toe of the hind-foot has a flat and nail-like claw. There are thirteen dorsal vertebrae, and the long tail has more than twenty. The clavicle is well developed, as in the other genera of this family. The large intestine of this animal is extraordinarily long; the proportions of the different regions of the gut are shown by the following measurements: small intestine, 820 mm.; caecum, 125 mm.; large intestine, 1340 mm. Such a disproportion between the large intestine and the small, to the advantage of the former, is a very strange fact in the anatomy of this Rodent.
The genus Lagidium (also called Lagotis), which includes "Cuvier's Chinchilla," is also a mountain dweller. There are several species of this genus, which differs from Chinchilla by the complete abortion of the thumb and of the great toe. The intestinal proportions are those of Chinchilla. The ears and tail are long. L. cuvieri measures 1-1/2 feet in length.
Lagostomus, again, has but one species, L. trichodactylus. The animal has a tail about half the length of the body. The digits are reduced as compared with Chinchilla, there being but four on the fore- and three on the hind-feet. There are only twelve dorsal vertebrae, and seven ribs reach the sternum. In the skull a distinguishing mark from the last two genera is the separation of the infra-orbital foramen into two by a thin lamella of bone. The large intestine is between one-half and one-third the length of the small intestine, and thus differs much from that of Chinchilla. {497}
FIG. 243.--Vizcacha. Lagostomus trichodactylus. x 1/10.
The Vizcacha lives in societies of twenty to thirty members,[371] in a "village" ("Vizcachera"), a dozen or so of burrows, which intercommunicate. They lie at home during the day and come out in the evening. Their burrows, like those of the Prairie Marmot, harbour other creatures, which apparently live on amicable terms with the Vizcachas; such are the burrowing owl, a small swallow, and a Geositta. The Fox also affects these burrows, but then he ejects the rightful owner of the particular burrow which he selects. When the young Foxes are born the vixen hunts the Vizcachas for food. The Vizcacha has a most varied voice, producing "guttural, sighing, shrill, and deep tones," and Mr. Hudson doubts if there is "any other four-footed beast so loquacious or with a dialect so extensive." These animals are very friendly, and pay visits from village to village; they will attempt to rescue their friends if attacked by a Weasel or a Peccary, and to disinter those covered up in their burrows by man.
FAM. 7. CERCOLABIDAE.--A number of the characters which differentiate this family from the Hystricidae or Ground Porcupines of the Old World are given under the description of the latter. The principal external characters are the prehensile tail, the admixture of spines with hairs, and the nature of the sole of the foot. In these points the New-World Cercolabidae differ from the Old-World Hystricidae. It is interesting to notice that {498} in both families we have long-tailed and short-tailed forms. Cercolabes corresponds to Atherura or Trichys, and Erethizon to Hystrix.
The genus Erethizon, the "Urson" of Canada, has a short, stumpy tail. Its spines are almost hidden by enveloping hair. The fore-feet have four, the hind-feet five toes. The short tail of this creature is remarkable when we reflect upon its climbing habits. It appears, however, to be a weapon with which it strikes sideways at the enemy.
FIG. 244.--Brazilian Tree Porcupine. Sphingurus prehensilis. x 1/6.
Of the Neotropical genus Cercolabes (sometimes called Sphingurus, Synetheres, or Coendou) there are some eight or nine species, all found in Central and South America. The animal is arboreal, and has in correspondence with that habit a prehensile tail. The spines are not so stout as in the Ground Porcupines, and are often coloured yellowish or reddish. In correlation with its tree-frequenting habits the bones of Cercolabes show certain differences from those of the Ground Porcupines. The scapula is broader and rounder in front than is that of Hystrix; the phalanges of the thumb (which is rudimentary) are fused together as in the Canadian Erethizon; but those of the very small hallux are also fused, whereas in Erethizon, as in Hystrix, they are separate. In one species, C. insidiosus, Sir W. Flower states that there are as many as seventeen dorsal vertebrae and thirty-six caudals. The tail is thus very long. In C. villosus there are fifteen dorsals and twenty-seven caudals; eight ribs reach the sternum, which is composed of seven pieces, the {499} sixth being very small. The clavicles are well developed. A curious fact about C. villosus is that the acetabular cavity is perforate (on both sides), or at least only closed by membrane. In many forms of Rodents the bone is very thin in this region. This fact perhaps lessens the significance of the perforation of the acetabulum of Echidna (see p. 109).
Of the allied genus Chaetomys, also Neotropical, there is but a single species, which inhabits Brazil. It has a nearly completely closed orbit, a feature which differentiates it from the last animal, and one which also shows it to be a more modified form. The spiny covering is less pronounced than in its allies.
FAM. 8. HYSTRICIDAE.--This family is characterised by the fact that all its members possess spines; but the tail, if at all long, is not prehensile, and the soles of the feet are smooth and not covered with rough tubercles, as in the Tree Porcupines of the next family, Erethizontidae. The clavicle is less developed than in the arboreal forms. In the organs of digestion there are points of a family difference between the two groups of spiny Rodents. The tongue has serrated scales arranged in transverse rows, which are directed backwards. A gall-bladder, though not always present, is sometimes found; it apparently never exists in the arboreal Porcupines and in Erethizon. The lungs show a great tendency to subdivision, which appears to be especially marked in the genus Atherura. The caecum seems also to be shorter in the Ground Porcupines. In Hystrix cristata the small intestine measures 15 feet 7 inches; the caecum, 8 inches; the large intestine, 4 feet 4 inches:--in Atherura africana the caecum measures 7-1/2 inches; the large intestine, 1 foot 10 inches. The corresponding measurements of Synetheres villosus were: small intestine, 7 feet 3 inches; caecum, 1 foot 4 inches; large intestine, 2 feet 7 inches. In Erethizon the caecum is 2 feet 4 inches in length. These differences are too large and too constant in a number of presumedly allied forms to be overlooked.
Mr. Parsons has directed attention[372] also to a number of muscular differences, such indeed as might be expected to occur between animals of such different habits.
The genus Hystrix embraces the better-known Porcupines. It is a genus of wide range, extending from the East Indies to Africa, {500} and even occurring in Europe. There are several species, of which the common Hystrix cristata is the best known, and is the one which is to be found in Europe.
FIG. 245.--Common Porcupine. Hystrix cristata. x 1/10.
The spines of the common form and of the others are solid in the middle of the body, but on the tail they are expanded into hollow quills, which make much rattling. They are as a rule black and white, the middle of the spine being banded with black. A great crest of coarse long hairs on the head is responsible for the scientific name of the well-known form. Sometimes in this genus, as in the Tree Porcupines of Brazil, the spines are orange or yellow; but it is said that the colour is soon lost in this country. As a matter of fact it is the easiest thing in the world to wash out with ordinary tap-water much of the yellow colour of the spines of the South American Sphingurus. The same may be the case with the pigment of the Old-World Porcupines. There are fourteen to fifteen dorsal vertebrae and four or five lumbars. The tail varies in length, but is shorter than the long tail of the arboreal New-World forms. It seems impossible when mentioning the Porcupine to escape from some observations about its alleged habit of shooting its quills. For some reason or other Buffon has got the credit of inventing, or at {501} least promulgating, this legend, which has even grown so in the telling that the quills are said to be capable of penetrating planks of wood. What Buffon said apropos of this matter is, "The marvellous commonly is pleasingly believed, and increases in proportion to the number of hands it passes through." It is of course the rattling of the spines and the occasional falling out of loose ones which has started the legend. They are, however, excellent weapons of offence, and the animal charges somewhat backwards to make the best use of them against the foe. The spines, however, are by no means an absolute protection, since, as Mr. Ridley informs us,[373] Tigers will kill and eat these animals just as the Thylacine is apparently indifferent to the spiny armature of Echidna.
Of the Brush-tail Porcupine, Atherura[374] there are at any rate two species, the West African A. africana and the Malayan A. fasciculata. It is interesting that the gap in the present distribution is partially filled by the discovery of fossil teeth near Madras. The genus does not differ widely in external appearance from Hystrix; it has, however, a rather longer tail; there are fewer large spines, and there is a tuft of them at the end of the tail, whence is derived the name of the genus. The frontal bones project a little distance between the nasals, a feature which does not seem to appear in the true Porcupines. There are fourteen dorsal vertebrae and five lumbars. The twenty-four caudal vertebrae of this Porcupine shows how much longer is its tail than that of Hystrix; for in the latter twelve is about the number.
A third genus of Old-World Porcupine is the singular Trichys.[375] Of this there is but one species, T. lipura. It is a curious fact that out of three examples, all from Borneo, two were quite without a tail. But this appears to be merely a mutilation, though it is singular that the natives state it to be without a tail. One cannot help thinking of the way in which lizards sometimes shed their tails when pecked at. The tail of this genus is more than half the length of the body and head. Trichys has sixteen dorsal and six lumbar vertebrae. There is a tuft of quills at the end of the tail, which are thin and compressed, {502} though truncate at the free extremity and hollow; they represent in a more rudimentary way the much stronger tuft at the end of the tail of other Porcupines. It is a curious fact that this and other Porcupines possess a mechanism for warning their foes precisely comparable to that of the rattlesnake. There are sixteen dorsal vertebrae.
SUB-ORDER 2. DUPLICIDENTATA.
The chief feature of this group is the existence of two pairs of incisor teeth in the upper jaw, of which the inner are very small and lie behind the outer. In the skull the infra-orbital foramen is small; the incisive foramina are very large. The tail is short or absent.
FAM. 1. LEPORIDAE.--This family is distinguished from the Lagomyidae by the long ears, by the tail, which is present, though short, and by the longer limbs. There are six teeth belonging to the molar series in the upper jaw, and five of the same in the lower. The clavicle is imperfect.
The longest known genus of this family, Lepus, was, until the quite recent discovery of Romerolagus, the only genus. It is of universal range, excepting Australasia and Madagascar, and consists of about sixty species. These are the Hares and Rabbits, to the former being assigned the longer-limbed forms.
As every text-book of zoology contains a more or less elaborate account of the structure of the Common Rabbit, and as there is but little structural difference between the members of the genus, a short account of the generic peculiarities of Lepus will suffice here. The fore-feet are five-toed, the hind-limbs four-toed. The hairy integument enters the mouth cavity, and the inside of the cheeks have a hairy covering. The soles of the feet are, moreover, hairy. The maxillary bones are curiously sculptured.
FIG. 246.--Lepus cuniculus. Skull. A, Lateral view; B, ventral view. ang.pro, Angular process of mandible; as, alisphenoid (external pterygoid process); aud.me, external auditory meatus; b.oc, basioccipital; b.sph, basisphenoid; cond, condyle; cor, coronoid process; fr, frontal; int.pa, inter-parietal; ju, jugal; lcr, lachrymal; max, maxilla; nas, nasal; opt.fo, optic foramen; o.sph, orbitosphenoid; pa, parietal; pal, palatine; pal.max, palatine plate of maxilla; pal.p.max, palatine process of premaxilla; par.oc, paroccipital process; peri, periotic; p.max, premaxilla; pt, pterygoid; p.t.sq, post-tympanic process of squamosal; s.oc, supraoccipital; sq, squamosal; ty.bul, tympanic bulla; vo, vomer; zyg.max, zygomatic process of maxilla. (From Parker and Haswell's Zoology.)
The Common Rabbit, L. cuniculus, differs from the Common Hare in the comparatively shorter ears and legs. The ears have not, to so marked a degree, the black tips of those of the Hare. The animal, moreover, produces naked young, and lives in burrows of its own excavation. A difference in the structure of the caecum, which distinguishes the Rabbit from the Hare, has been {504} pointed out by Professor W. N. Parker.[376] These differences have led some to approve of its separation from the Hares into a genus Oryctolagus. This animal is believed to be an introduced species, and to have been brought by man into these islands. Its original home is the Spanish Peninsula, the south of France, Algiers, and some of the Mediterranean islands. Mr. Lydekker thinks that the only other species of Lepus which can be considered to be a "Rabbit" is the Asiatic L. hispidus.
Of Hares there are two species in this country. The Common Hare, L. europaeus (the name L. timidus seems to be really applicable to another species to be referred to presently), extends all over Europe excepting the extreme north of Russia and Scandinavia. It is not known in Ireland, and, curiously enough, attempts to acclimatise this animal in that island have failed--a state of affairs which contrasts with the fatal ease with which the Rabbit has been introduced into Australia. Ireland has, however, the Variable Hare, L. timidus (also called L. variabilis), a species which is common in other parts of Europe, and which extends as far east as Japan. This species differs from its ally by the fact that it often turns white in winter with the exception of the black tips to the ears. In Ireland this change does not always occur; but Mr. Barrett-Hamilton has commented upon the fact that Hares of this species do change on Irish mountains. It appears that in this animal the change from the winter to the summer dress is accomplished by the actual casting off of the white hairs and their replacement by a fresh growth of "blue" hairs. A similar change occurs in the American L. americanus.
Dr. Forsyth Major has noted the fact that the various species of Hares can be distinguished by the condition of the furrows upon the upper incisors. Thus two African species, L. crawshayi and L. whytei, are to be separated by the fact that in the former the incisors are quite flat, whereas in L. whytei the groove is more prominent and there is a second shallow furrow.
The genus Romerolagus[377] is quite a recent discovery. It occurs on the slopes of Popocatepetl in Mexico; it has the general aspect of the last genus, and is spoken of as a "Rabbit." It inhabits runs in the long grass which clothes the sides of the {505} mountain. Externally it is something like the Pikas, since it has no tail visible. The ears, too, are short, and the hind-legs comparatively short. The skull is very like that of the Rabbit; but in other osteological details it is aberrant. Thus the clavicle is quite complete, and only six ribs articulate with the sternum, instead of the seven that we find in the Rabbit.
FAM. 2. LAGOMYIDAE.--The animals of this family are smaller than the Hares and Rabbits; they have short Vole-like ears and no external tail. The limbs also appear to be shorter. As there is but a single genus, the characters of the family may be described in connexion with those of the genus, which is known as Lagomys (apparently more correctly Ochotona). Of this genus there are about sixteen species, which are mainly Asiatic; one species extends its range into Eastern Europe, and three are North American.
The skull has not the supra-orbital grooves of the Rabbits, and has a well-marked backward process of the zygomatic arch. There are eighteen dorsal vertebrae. The molars and premolars are five.
The vernacular names of "Pika" and "Piping Hares" have been applied to the members of this genus, the latter on account of their peculiar call. They live among rocks in companies and they burrow. They are usually found at considerable altitudes: thus L. roylei, the "Himalayan Mouse Hare," is found at elevations as high as 16,000 feet; while L. ladacensis gets even higher, 19,000 feet having been recorded. With the habits of a Marmot, so far as concerns living in burrows and at great altitudes, the animals of this genus, with their squat form and short ears, are not unlike those animals. In the past this genus occurred more generally over Europe. Species from Miocene beds have been met with in England, France, Germany, and Italy.
FOSSIL RODENTS.--Quite a large number of existing genera of Rodents are known from even the earlier strata of the Tertiary period. The Squirrels (and even the genus Sciurus itself) occur in the Upper Eocene. So, too, do the genera Myoxus, and (in South America) Lagostomus. Spermophilus, Acomys, Hystrix, Lagomys, Lepus, Hesperomys are known from Miocene rocks. Rhizomys, Castor, Cricetus, Mus, Microtus, and some others appear to have originated so far as we know in the Pliocene, while a still larger series of existing genera are Pleistocene. It is interesting {506} to note that some of the extinct genera were much larger than recent forms. At present, Hydrochoerus is the biggest Rodent; but the genus Megamys from the Pampas formation of Argentina was "nearly as large as an ox." The wider range of genera in the past is illustrated by Hystrix, which, now an Old-World form, is represented by remains in the Miocene and Pliocene of America.
It is a significant fact that of living genera Sciurus is the oldest; for it has been pointed out that in a number of features the Squirrels are among the most primitive of Rodents. The zygomatic arch is slender, and has thus not acquired the specialisation that is to be found in that part of the skull in other Rodents; moreover, the "jugal bone is not supported by any process from the maxilla exactly as in the primitive Ungulata." The feet, too, are unspecialised, though that is the case with many other genera. It may also be pointed out that the teeth bear not a little likeness to those of Ornithorhynchus in their multituberculate character.
Some few fossil forms have already been dealt with in the preceding pages.
The two genera Castoroides and Amblyrhiza, from the Pleistocene of North America and the West Indies, are usually regarded as forming a family. The skull of the former genus indicates an animal of the size of a Bear. It is compared to that of Castor, but it has a wide infra-orbital foramen. The teeth are four in each jaw, and are formed of three to five lamellae; the incisors of this animal are powerful but short. Amblyrhiza, on the other hand, has long incisors which are longitudinally grooved anteriorly. It has a free fibula. This latter as well as other characters have led Tullberg to remove it from association with Castoroides.
ORDER X. TILLODONTIA.
This group of Eocene mammals is to be defined by a number of characters, of which the more important are the following:--The incisors are enlarged, grow from persistent pulps, and are coated with enamel upon the outer surface only; they are those of the second pair only, the first and third having disappeared or become small. The canines are reduced in the later forms. {507}
FIG. 247.--Tillotherium fodiens. Left lateral view of skull. (From Flower, after Marsh.)
These animals have been regarded as ancestral Rodents, to which the tooth characters just mentioned clearly show likenesses. The earliest known form is Esthonyx. This genus shows such primitive characters, compared with its later representatives, as the existence of all three pairs of incisors in the upper jaw, but only two in the lower jaw. The enlarged incisors of both jaws do not seem to have grown from persistent pulps.
Anchippodus, a later form, still preserves the upper pair of first incisors in a vestigial form; the strong second incisors grew from persistent pulps. The most recent genus, Tillotherium, shows the characteristics of the group at their height. The strong Rodent-like, chisel-shaped incisors, which are reinforced by a small additional pair in the upper jaws only, are persistent. The grinding teeth are of the tritubercular pattern; there are three of each kind in the upper jaw, but in the lower jaw only two premolars on each side. This is at any rate the case with some, while others have three. The canine, though present in both jaws, is insignificant. As in many ancient types, there is an entepicondylar foramen in the humerus. The feet were five-toed, and bore sharp, laterally-compressed claws. The skull has been compared in general aspect to that of a Bear.
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