Natural history of the American lobster ..

Front matter

NATURAL HISTORY. OF THE AMERICAN LOBSTER ^ ^ ^

From bulletin pF THE BUREAU' OF FISHERIES, Volume XXIX, 1909 Document No:. 747 : ; .• ; : ; ; ; : ; ; ; ; Issued July xj, 1911

WASHINGTON

Introduction

Chapter I. The lobsters and allied Crustacea; their zoological relations, habits, development,

and use as food

Natural history of the Crustacea

Development of the Crustacea

Family life in crayfish

II. The American lobster; its economic importance and general habits

Geographical range

History and importance of the lobster fisheries in brief

Capture, transportation, and acclimatization of the lobster

Habits and instincts of the adult lobster

Migratory instincts

Movements of tagged lobsters

Movements off Cape Cod and at Woods Hole

Optimum temperature

Influence of light and nocturnal habits

Burrowing habits

Food and preying habits

Cannibalism '

Review of the instincts and intelligence of the adult lobster

Color in the adult

III. Giant lobsters

Greatest size attained by the lobster

IV. Molting

The skin and shell

Periods, conditions, and significance of molting

The molting act

Withdrawal of the big claws

Molting of the “hammer claw” in the snapping shrimp Alpheus

Changes in the skeleton preparatory to molting

The gastroliths or stomach-stones

Hardening of the new shell

Relation of weight to length in adult

Proportion of waste to edible parts in the lobster

V. Enemies of the lobster

Predaceous enemies

Parasites and messmates

Diseases and fatalities of the lobster

VI. Anatomy of the lobster, with embryological and physiological notes

Body

Internal skeleton and head

Appendages

Mouth parts

The slender legs

Central nervous system

Peripheral stomato-gastric system

Sense organs

ISO

IS3

170 170

201 204

215 215 215

Page,

Chapter VI. Anatomy of the lobster, with embryological and physiological notes — Continued.

Sense organs 232

Eyes 232

Sensory hairs 234

Relation of setae to hatching and to molting 235

Touch, taste, and smell 236

Balancing organs or statocysts 238

Muscles 241

Blood and organs of circulation 242

Heart 243

Pericardial sinus 243

Arteries 244

Arterial supply of the swimmerets 245

Gills 246

Branchial cavity and respiration 247

Course of the blood in the gill 248

Alimentary tract 249

Grinding stomach 249

Liver 251

Kidneys or green glands 252

VII. The great forceps, or big claws 253

The crustacean claw 253

The great chelipeds 254

Lock hinges of big claws 255

Asymmetry in the big claws of the lobster 256

Torsion of the limb 257

Breaking plane and interlock 259

The toothed claw or lock forceps, and its periodic teeth 260

The cracker, or crushing claw 264

Development of the great forceps 266

Variation in position of the great forceps 274

Symmetry in the big claws 275

Changes in the toothed claw at molting 278

VIII. Defensive mutilation and regeneration 281

Autotomy or reflex amputation 281

Restoration of lost parts 283

Monstrosities 285

IX. Reproduction 288

Sexual distinctions 288

The ripe ovary .. ' 289

Development of the ovary to the first sexual period 290

Cyclical changes in the ovary after the first sexual period 291

Disturbances in cyclical changes in the ovary 292

Period of adult life or sexual maturity 293

Limits of the breeding season 294

Frequency of spawning 295

Number of eggs produced 298

Breeding habits and behavior in crayfish 300

Pairing habits in the lobster 302

Preparation for egg laying: Cleaning brushes of the lobster 303

Egg laying 305

152 BULI.ETIN OB THE BUREAU OF FISHERIES.

Chapter IX. Reproduction — Continued. Page

Arrangement and distribution of the eggs and their attachment to the body . . 305

Origin of the egg glue and fixation of the eggs 306

The oviduct and its periodic changes 307

Comparisons with other Crustacea, and theories of fixation 308

The male sexual organs 312

Sperm cells; their origin and structure 312

Fertilization 315

The seminal receptacle, copulation, and impregnation 318

X. Development 320

Analysis of the course of development 320

Embryo 322

Exclusion and dispersal of the brood 326

Hatching process 327

First larva 329

Color of the larva 331

Structure and habits 332

Natural food of the larva 335

Second larva 337

Third larval stage 338

Fourth or lobsterling stage 340

Color in the fourth stage 341

Fifth stage 342

Sixth stage 344

Seventh stage 344

Eighth and later stages 346

Habits of adolescent lobsters 346

A lobster 413 days old 347

When does the young lobster go to the bottom to stay? 347

Food and causes of death in artificially reared lobsters 349

Significant facts of larval and later development 350

XI. Behavior and rate of growth 353

Behavior of young lobsters 353

Reactions to light 354

Reactions to other stimuli 356

Movements of the young lobster in a state of nature 357

Variation in the rate of growth and dmation of the stage periods 358

Conditions which determine the rate of growth and duration of the stages. . . 359

Rate of growth and age at sexual maturity 360

XII. The preservation and propagation of the lobster 367

The fact and cause of decline of the fishery 367

The problem 369

How the problem has been met 369

Closed seasons 370

Protection of berried lobsters 370

The gauge law 371

The life rate or law of survival 375

Propagation of the lobster 379

Recommendations 382

Bibliography of the lobster — Homanis 384

INTRODUCTION.

The present work when originally undertaken in 1903 was designed to form the zoological part of a history of the lobster in both America and Europe, but subsequent events led to a modification of this plan, and when it was decided to issue this section separately, its character and scope were somewhat changed.

Dr. Hugh M. Smith, of the United States Bureau of Fisheries, had planned to deal with the lobster fishery and the economic questions which this great industry has raised, in a comprehensive manner, and hope is entertained that this design may still be carried out.

Though essentially a distinct work, this is in a measure both a revision and an extension of my earlier report upon The American Lobster, published by the United States Commission of Fish and Fisheries in its bulletin for 1895. But little from the latter, however, has been incorporated directly, and this only when newer or better research has failed to give us more light upon the subject. Six drawings of the young lobsters, three of which are in colors, have been reproduced, after slight revisions, from my former report ; all of the rest are new and deal chiefly with the anatomy of the body and appendages, especially with torsion, reflex amputation, and the developmental history of the toothed and cracker claws, the sexual organs, and the germ cells. I have depended mainly upon the store of materials collected in former years, but have received accessions from the United States Bureau of Fisheries, for which as well as for many courtesies, now extending over a long period, I wish to offer my sincere thanks. The Bureau has generously given me the privilege of a free lance, and all critical sections of this paper should be read in the light of individual opinion only, directed, it is true, in a friendly spirit, and as we believe from the standpoint of science.

Our knowledge of the lobster has increased to such an extent during the past fifteen years that in all probability there is no marine invertebrate in the world which is now better known. This result is due to the suggestive ideas or elaborate researches of a large body of naturalists in both America and Europe, and to their labors the reader will find abundant reference in the pages which follow. As a result of this advance in the biological field, a signal success has been achieved in the artificial propagation or culture of the lobster, and particularly in rearing the delicate young to the bottom-seeking stage, a success from which this fishery should not be slow to profit, and which it owes to experiments begun under the auspices of the United States Fish Commission at Woods Hole, Mass., and afterwards carried to a high degree of perfection by the Commission of Inland Fisheries of Rhode Island, under the direction of Prof. Albert D. Mead, at Wickford. Through the aid of such a practical method there is ground for hope, not only of restoring our depleted fisheries on the Atlantic coast, but of establishing new ones on the Pacific, as well as in other parts of the world.

bulletin of the bureau of fisheries.

While many dark puzzles have been solved, and many questions, raised fifteen years or more ago, can now be answered with assurance, no enterprising or resourceful worker need be told that the field is still fertile for fuller or more exact researches in many directions. We hope that some of these subjects will be suggested by the imperfections of the present work when attention is not called to them directly.

F. H. HERRICK.

Cleveland, Ohio.

PLATE XXVIII

NATURAL HISTORY OF THE AMERICAN LOBSTER.

By FRANCIS HOBART HERRICK, Ph. D., Sc. D.,

Professor of Biology, Western Reserve University, Cleveland, Ohio.

J-

Chapter I.— THE LOBSTERS AND ALLIED CRUSTACEA; THEIR ZOOLOGICAL RELATIONS, HABITS, DEVELOPMENT, AND USE AS FOOD.

NATURAL HISTORY OF THE CRUSTACEA.

Nature works according to definite principles, and with a degree of uniformity which for most of our purposes is practically absolute. Accordingly we find that whenever an animal or plant has been successfully domesticated or whenever the young of any form have been successfully reared by the artificial impregnation and subsequent care of the eggs, as in the case of the oyster or the whitefish, this has been accomplished by acting, whether intelligently or not, in accordance with the principles of nature. The mollusk or the vertebrate is made to yield to experiments which a knowledge of its habits and structure would suggest. In the lobster we have to deal with another and distinct type, for although this animal swims in the sea, it is not a fish, but an arthropod, and a knowledge of the ways of fishes and mollusks will help but little in the study of its habits or in the propagation of its race.

The following paragraphs on the general characteristics of the arthropods will be of little or no use to professional zoologists, but may help to set our subject in a clearer light for other readers.

Of the eight or more animal types recognized by naturalists the arthropods are distinguished for their complicated structure and wonderful diversity of form, for the wide range and specialization of their instincts, their almost unparalleled fertility and corresponding activity. In the latter respect, at least, some of the insects are not surpassed by birds, the most active vertebrates.

The body of the arthropod is composed of a series of successive segments, the somites or metameres, which in conformity to vertebrate anatomy are divided into three groups, pertaining to the head, thorax, and abdomen. (PI. xxxiii, and table 4.) Theoretically, each somite at one time possessed a pair of jointed limbs, and many of the segments still retain them. In the living adult state, the body is normally maintained in a definite upright position, which is often one of unstable equilibrium, whether the animal is in motion or at rest. These characteristics are shared in some degree by the annelid

BULLETIN OF THE BUREAU OF FISHERIES.

worms, their nearest allies, as well as by the vertebrates. The arthropod possesses in addition a dorsal brain, united by a ring-commissure about the esophagus, to a ventral chain or “ladder” of paired ganglia, a character also shared by the higher worms; the heart is dorsal and overlies the food canal ; the cuticle, which encases the body and lines every inward fold, is secreted by the outer layer of the skin, the epidermis or hypodermis, and is chitinous — that is, contains chitin, a complex nitrogenous substance, by some chemists regarded as analogous to cellulose and lignin, which occur typically in plants and form the basis of all their woody tissues. This cuticle of the Crustacea is often reinforced by thick deposits of lime and other minerals, thus forming a hard external skeleton, to which every peripheral muscle is directly or indirectly attached, and by which every soft and delicate organ in the entire body is protected. No other animals possess all the several characteristics just enumerated. Since the arthropods embrace the insects, with their hundreds of thousands of species, it is not surprising that according to some estimates they include three-fourths of all the known species of living animals.

Of the five commonly recognized classes of arthropods the Crustacea are the lowest and most primitive. They fall into two principal subclasses: (a) The Entomostraca, embracing all the simpler, more primitive and generally smaller forms, such as water fleas, copepods, and barnacles, and (b) the Malacostraca, to which pertain the larger and the most highly organized of living Crustacea, such as lobsters, shrimps and crabs. The ancient name of the class Served the older zoologists to distinguish those animals which possessed a “crust,” or a shell flexible at certain joints, from the Testacea, or animals like the oyster and clam in which the shelly covering was a hard and unyielding “test. ”

Eight orders of Malacostraca® have been recognized, of which the more important, in view of their size, numbers, economic and general zoological interest, are the Amphipoda and Isopoda, which embrace the beach fleas on the one hand and terrestrial wood lice on the other; the primitive Stomatopoda, of which the edible mantis or “praying” shrimp are well known representatives, the small Schizopoda, or cleft-feet, and the ten-footed and stalk-eyed Decapoda, which mainly interest us.

In both the isopods and amphipods the eggs are carried in a brood chamber on the underside of the thorax, formed by membranous plate-like outgrowths from the thoracic legs in the female; the schizopods also carry their eggs in a similar way.

The breeding habits of the stomatopods are highly peculiar; although celebrated for their widely dispersed pelagic larvae, and although it was understood that they dwelt in mud burrows under water, and did not carry their eggs attached to the body as in decapods, little was known of their early life history until the studies of Professor Brooks upon Gonodactylus chiragra of the Bahama Islands appeared in 1893, when he gave the first full account of their habits, and the first record of the rearing of a young stomatopod from the egg. Fortunately this animal does not deposit its ova deep in the mud, but in a burrow, apparently of its own making, in the soft coral rock; they are glued together by a viscous cement and molded to fit the convex form of the mother’s

“ In the classification briefly outlined in this chapter we shall follow mainly the excellent work on Crustacea by Geoffrey Smith, in vol. iv of the Cambridge Natural History. London, 1909.

NATURAL history OF AMERICAN LOBSTER.

body. With its egg cluster on its back Gonodactylus stands or sits on guard at the mouth of the burrow, awaiting its prey, and meantime keeping its eggs aerated by the fanning movements of the swimmerets. Says Professor Brooks:

When the burrow is broken open she quickly rolls the eggs into a ball, folds them under her body in a big armful, between the large joints of her raptorial claws, and endeavors to escape with them to a place of safety. The promptness with which this action is performed would seem to indicate that it is an instinct which has been acquired to meet some danger which frequently presents itself.

The decapods have the general characteristics given for the lobster in chapter vi. All glue their eggs to their swimmerets and carry them thus attached, protecting and aerating them for a period of weeks or months with unerring instinct until they hatch. After pairing, the sexes frequently separate, as is possibly the case with lobsters (see p. 302), or they remain together, swimming side by side, and receiving mutual aid as in Stenopus, for as long at least as the period of fosterage lasts. The young, upon hatching, usually either swarm together for a time, or are immediately dispersed, as in the lobster. A long and perilous metamorphosis awaits the young of most of the decapods, during which they are pelagic or free surface swimmers, but every degree of abbreviation of this development exists, and in the crayfishes and certain other species, both fluviatile and marine, the young resemble the parent at birth, and a complex family life, which will receive attention later, may be developed.

The decapods are divisible into three intergrading suborders: (i) The Macrura, or long-tailed Crustacea like the shrimp and true lobsters; (2) the Anomura or hermit lobsters and hermit crabs, and (3) the Brachyura or true crabs, the most highly specialized of the entire class, in which the tail is not only very short but is even rudimentary in the male.

To follow out the Macrura only and in brief, they embrace numerous families possessing both zoological interest and economic value, of which the most important are (i) the Nephropsidse (Astacidse of many authors) or true lobsters; (2) the fresh-water crayfishes of the world, or Astacidae of North America and Europe, and the Parastacidse of the Southern Hemisphere; (3) the other decapods known collectively as prawns or shrimps, including the Peneidae, Alpheidae, Pandalidae, Crangonidae, and Palaemonidae ; (4) the Palinuridae, variously known as spiny, thorny, or rock lobsters, and (5) the Scyllaridae, which are sometimes classed with the Galatheidae, and are known as warty lobsters. Representatives of some of these families will now be briefly considered, before dealing more fully with the special subjects of this work embraced in the family of Nephropsidae.

The crayfish (of the family Astacidae) has become a favorite subject in zoology, and very few invertebrates have received the degree of attention which naturalists have paid to every phase of its history. It is well known that the common crayfish, Astacus fluviatilis, has been used for centuries as food all over the continent of Europe, while in France the farming of crayfish in order to increase the natural supply of this crustacean has been successfully practiced for some time. For many years also crayfish have found their way to the markets of American cities which possess large populations of foreign birth, as New York, New Orleans, Chicago, Milwaukee, and San Francisco; but many persons would probably be surprised to learn the present status of the craybulletin of the bureau op fisheries.

fish industry in this country, where vast numbers are not only eaten but used to supply classes in zoology or some phase of nature study in nearly every State of the Union.

Professor Andrews,® from whose paper the following statistics are taken, thinks that the demand for the fluviatile crayfish is likely to grow steadily, and may help to counterbalance the waning supplies of marine food, especially in the form of lobsters and crabs.

The crayfish of the eastern central regions belong to the genus Cambarus, the Potomac supplying C. affinis; Chicago, C. virilis; New Orleans, C. blandingii; and Montreal, C. bartoni. A considerable fishery for the large and handsome American species of Astacus, a counterpart of the European form, has been developed on the Pacific coast. This centers in Portland, Oreg., where, in 1899, the product reached 1 17,696. pounds, valued at $19,556.

Andrews has shown that the common Cambarus affinis not only breeds annually, but that its young reared from spring eggs may in turn lay eggs the spring following, when under a year old, while at the age of 3^ years they attain the average market size of 4 inches. It is further suggested that the large 6-inch Oregon Astacus, which is more lobster-like in appearance, could doubtless be successfully introduced into Eastern waters, and, with a growing demand, profitably reared, since there is no reason to suppose that climatic changes would offer any obstacle to its development.

The prawns and shrimps distributed among the various families enumerated are undoubtedly the most active and most graceful, as well as the most plentiful of all the decapod Crustacea. Many species are highly valued as food, and are netted and sent to market in vast numbers over a large part of the world. The most important shrimp fisheries of the United States center in the Coast States of the Gulf of Mexico and Pacific Ocean.

Among the best-known species in North America are the edible shrimp of the South {PencEus setiferus and P. brasiliensis) , the still more abundant common shrimp (Crangon vulgaris), found on both coasts and closely related to the common European shrimp The California shrimp {Crangon jranciscorum) , the largest and most important of the edible species on the western coast, attains a length of 3X inches. It not only supplies abundantly the local markets, but occupies an important place in the export trade of San Francisco, being boiled, dried, and shipped to China in large quantities.

Prawns are extremely abundant in the East Indies from Japan’ to Australia, and, commercially considered, are the most important Crustacea of the Orient. Thirteen species of the genus Penccus alone are taken in Japanese waters. “They are highly prized and extensively used as food and bait, and dried prawns annually exported to China amount to about 900,000 kilograms in weight and to about 200,000 yen ($131 ,000) in value. The dried prawns belong almost exclusively to the genus P emeus.

Closely allied to prawns, though placed in a distinct family, are the Alpheidae, of which over 100 species of snapping shrimps belonging to the genus Alpheus and Synalpheus alone have been described. They are essentially tropical, and abound in

“ Andrews. E. A.: The future of the crayfish industry. Science, n. s., vol. xxm, 1906, p. 983-986. New York.

6 Eishinouye, K.; Japanese species of the genus Penaeus. Journal of the Fisheries Bureau, Tokyo, vol. vm, 1900, no. i, p. 1-29.

NATURAL HISTORY OF AMERICAN LOBSTER.

the coral seas of both hemispheres. The Alpheidae have no commercial value, but are of great biological interest, on account of their wide variation in form, coloring, and development, as well as for their remarkable instincts and habits.

The large and handsome spiny or thorny lobsters (family Palinuridse) are represented chiefly by the single genus Palinurus. The langouste of the French, which has been celebrated from antiquity, is noted for its great size, brilliant coloring, and formidable appearance, though claws are lacking, as well as for its small and numerous eggs and grotesque transparent larvae. Its flesh, which is mainly confined to the thorax and tail, is considered by many quite as delicate as that of the true lobsters. From 13 to 16 speeies have been described from the temperate and tropical seas of the world. Aceording to Spence Bate,® this genus is represented in the South Indian Ocean by Palinurus edwardsii, the range of which extends from the Cape of Good Hope to New Zealand, by Palinurus trigonus and allied forms in Japan, by Palinurus frontalis on the coast of South America, and by Palinurus longimanus and related species in the West Indies. The common spiny or rock lobster {Palinurus vulgaris) of southern and western Europe is an important article of marine food, particularly in France and on the coasts of the Mediterranean Sea and its islands. It is commonly seen in the markets and restaurants of London, where it commands a good price.

According to Ritchie,* Palimirus vulgaris occurs on all the shores of the British Isles except a part of the east coast to the north of Flamborough Head. It is most abundant in the southwest, and scarcer northward, but is frequently debarred from entering traps on account of its stout, unyielding antennae. Palinurus in the adult state is unknown in the North Atlantic Ocean north of the Bermuda Islands, but its pelagic larvae are undoubtedly borne far to the northward by the Gulf stream. It is represented on the western coast of North America by Palinurus interruptus.

The carapace of the langouste is not “buttoned” to the tail so effectively as in the common lobster; a|l the thoracic legs end in long dactyls with indurated tips, which are studded with dense bunches of stiff setae. The first two pairs of legs are greatly elongated, and the tactile setae of their dactyls, which resemble bottle brushes, exhibit an extraordinary development.

The largest of the scaly or warty lobsters is represented by Scyllarus, whieh occurs both in the Mediterranean and the North Atlantic Ocean, and is said to attain a length of 18 inches and to excel all other lobsters in the quality of its flesh. Their quadrangular, flattened shell and small, slender legs give them a singular appearance, but specially remarkable are the short, scale-like antennae, which are possibly used as shovels or scoops in burrowing. Their small and widely separated eyes are completely embedded in the carapaee, which is studded all over with wart-like tubercles, thus giving it a granulated and leathery texture, while on the inside it has the appearance of a fine sieve of uniform pattern. Each hole gives passage to a bundle of tactile setae, which spread in the upper layers of the shell and issue through minute pores

“ Bate, Spence: Report on the Crustacea Ma London, 1888.

!> Ritchie, James: Distribution of Palinuru: Xxm, p. 68-71. Edinbmgh, 1910.

esults of the voyage H. M. S. Challenger; Zoology, vol. xxrv. . Proceedings of Royal Physical Society of Edinburgh, vol.

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Upon the tubercles or around their margins. The last pair of thoracic legs, in the females only, bear claws, which led to the fanciful notion that they were used by the mother in rupturing the eggs and liberating the young. The eggs are very small, and, as in Palinurus, the young issue in the peculiar transparent larva known as phyllosoma.

The whole front of Palinurus guttatus is armed with stout spines culminating in a pair of rostral horns, which in large specimens rise vertically to the height of an inch oi;more in parallel planes, thus shielding the eyes and presenting one of the most effective types of protective armature to be seen in an adult crustacean. The antennules are extremely long and slender, while the antennae have very stout basal stalks, and long stiff flagella, encircled at intervals with sharp teeth, like the war mace of a South Sea Islander.

The second segment of the antenna bears a notable structure, usually described as a stridulating organ. The inner surface of this division is free, and carries a pad and flap which, with the movements of the antenna, plays backward and forward over a smooth ridge or track on the somite. The sound, which it is said may be heard in or out of water and may be produced artificially after death, is evidently caused by friction of the hard chitinous surface of the pad on the track over which it slides. (See p. 240.)

The California spiny lobster, according to Rathbun, may attain a length of 14 inches, and an average weight of 3T3 pounds, the greatest weight recorded being pounds. The usual length of Palinurus vulgaris, as given by Bell (ao)“ in 1853, was about a foot, but 18 inches was sometimes reached. His description was from a male of the latter size, which weighed 5 pounds. “I can not but think,” said Bell, “that Dr. Milne Edwards is greatly mistaken in attributing to individuals of that size a weight of from 12 to 15 pounds. ” The Californian langouste is most abundant on the southern part of the coast. It is often trapped in great numbers, but even twenty years ago we are told by Rathbun that the species was in danger of extermination from overfishing.

Artificial propagation of the Japanese spiny lobster, Palinurus japonicus Gray, was undertaken by the fisheries institute, near Tokyo, previous to 1899, and a report of progress was published in that year. Great difficulty was experienced in handling the larvae, on account of their minute size and long metamorphosis. The spawning and hatching periods of this lobster, as I am informed by Tasute Hattori, who conducted the experiments, extend from late April to late September. The larvae were easily hatched, but gradually died off after the fifteenth or sixteenth day. No success had been attained in 1901, since which time no further information has been received.

The Nephropsidae, the best known of the Crustacea, on account of their high commercial value as food, are represented by three species, the Norwegian lobster, Nephrops norvegicus Einnaeus, the common lobster of Europe, Homarus gammarus Linnaeus, and the common lobster of America, Homarus americanus Milne Edwards.

The technical names for the lobsters adopted in a former work {149) are here retained, pending a decision upon the question by the International Committee on Nomenclature of the International Zoological Congress, which met in Boston in 1907.

“ Italic figures in parentheses refer to works enumerated in the bibliography at the end of this paper.

NATURAIv HISTORY OF AMERICAN FOBSTER.

i6i

The question of the validity of Tatreille’s types in his “Considerations Generales . . of i8io, has been raised by Stebbing, who would restore the terminology of Leach, designating Astacus Potamohius and Homarus Astacus.°'

Aside from the merits of this controversy, it may be well to point out again that Latreille and others who have followed him were wrong in asserting that Aristotle makes no mention of the river crayfish (j^p). On the contrary, the Father of Zoology uses the term dazaKOc to designate both crayfish and lobster, and so far as antiquity is concerned neither has the claim of priority.^

The Norwegian lobster is common not only to Norway but to the coasts of Scotland and Ireland. While essentially a northern form, it is found as far south as the Mediterranean but in much less abundance. It attains a length of from 7 to 8 inches, and in life is of a delicate flesh tint, boldly marked with light brown in symmetrical pattern over the abdomen and tail fan. Its slender form suggests. the shrimp type, and its large kidney-shaped eyes remind one of Penceus, and of the adolescent lobster {Homarus) when from i to 3 inches long. The claws of the first pair of thoracic legs are slender, of nearly equal size and keeled above, below, and at the sides, each keel having a single, or at the sides a double row of spines. Bell, writing at the middle of the last century, said of this species that it was frequently on sale in the Edinburgh markets, and was occasionally seen in London.