in zoology, a genus of insects belonging to the order of insecta aperta. The generic characters are these: they have eight legs, (feldom ten or six), besides the two large claws which answer the purpose of hands. They have two eyes at a considerable distance from each other, and for the most part supported by a kind of pedunculi or footstalks; the eyes are likewise elongated and moveable; they have two clawed palpi, and the tail is jointed. This genus includes the lobster, shrimp, &c. There are no less than 87 species of cancer, distinguished principally by the length of their tails and the margins of their breasts. The following are the most remarkable.
1. The gammarus, or common lobster, with a smooth common thorax, short serrated fin; very long antennae; and lobster between them two shorter ones, bifid; claws and fangs large, the greater tuberculated, the lesser serrated on the inner edge; four pair of legs; five joints in the tail; tail-fins rounded. It inhabits all the rocky shores of our island, but chiefly where there is a depth of water. In Llyn in Caernarvonshire a certain small lob- Lobsters fear thunder, and are apt to cast their claws on a great clap; it is said that they will do the same on the firing of a great gun; and that, when men of war meet a lobster boat, a jocular threat is used, that, if the master does not sell them good lobsters, they will salute him.
The habitation of this species is in the clearest water, at the foot of rocks that impend over the sea. This has given opportunity of examining more closely into the natural history of the animal, than of many others who live in an element that prohibits most of the human researches, and limits the inquiries of the most inquisitive. Some lobsters are taken by hand; but the greater quantity in pots, a fort of trap formed of twigs, and baited with garbage; they are formed like a wire mouse-trap, so that when the lobster gets in, there is no return. These are fastened to a cord sunk in the sea, and their place marked by a buoy.—They begin to breed in the spring, and continue breeding most part of the summer. They propagate more humanly, and are extremely prolific. Dr. Balfour says he counted 12,444 eggs under the tail, besides those that remained in the body unprotruded. They deposit these eggs in the sand, where they are soon hatched.
Lobsters change their crust annually. Previous to their putting off their old one, they appear sick, languid, and restless. They totally acquire a new coat in a few days; but during the time that they remain defenseless, they seek some very lonely place, for fear of being devoured by such of their brethren as are not in the same situation. It is also remarkable, that lobsters and crabs will renew their claws, if by accident they are torn off; and it is certain they will grow again in a few weeks, though they never attain to the size of the first. They are very voracious animals, and feed on sea-weeds, garbage, and all sorts of dead bodies. The pincers of one of the lobsters large claws are furnished with knobs, and those of the other are always serrated. With the former it keeps firm hold of the stalks of submarine plants, and with the latter it cuts and minces its food very dexterously. The knobbled or numb claw, as the fishermen call it, is sometimes on the right and sometimes on the left side indifferently. It is more dangerous to be seized by them with the cutting claw than the other; but, in either case, the quickest way to get disengaged from the creature is to pull off its claw. The female or hen lobster does not cast her shell the same year that she deposits her ova, or, in the common phrase, is in berry. When the ova first appear under her tail, they are small, and extremely black; but they become in succession almost as large as ripe elder-berries before they are deposited, and turn of a dark brown colour, especially towards the end of the time of her depositing them. They continue full, and depositing the ova in constant succession, as long as any of that black substance can be found in their body, which, when boiled, turns of a beautiful red colour, and is called their coral. Hen-lobsters are found in berry at all times of the year, but chiefly in winter. It is a common mistake, that a berried hen is always in perfection for the table. When her berries appear large and brownish, she will always be found exhausted, watery, and poor. Though the ova be cast at all times of the year, they seem only to come to life during the warm summer months of July and August. Great numbers of them may then be found, under the appearance of tadpoles, swimming about the little pools left by the tides among the rocks, and many also under their proper form from half an inch to four inches in length. In casting their shells, it is hard to conceive how the lobster is able to draw the fish of their large claws out, leaving the shells entire and attached to the shell of their body, in which state they are constantly found. The fishermen say, the lobster pines before casting, till the fish of its large claw is no thicker than the quill of a goose, which enables it to draw its parts through the joints and narrow passage near the trunk. The new shell is quite membranaceous at first, but hardens by degrees. Lobsters only grow in size while their shells are in their soft state. They are chosen for the table, by their being heavy in proportion to their size; and by the hardness of their shells on their sides, which, when in perfection, will not yield to moderate pressure. Barnacles and other small fish adhering to them are reckoned certain signs of superior goodness. Cock-lobsters are in general better than the hens in winter; they are distinguished by the narrowness of their tails, and by their having a strong spine upon the centre of each of the transverse processes beneath the tail, which support the four middle plates of their tails. The fish of a lobster's claw is more tender, delicate, and easy of digestion, than that of the tail. In summer, the lobsters are found near the shore, and thence to about six fathoms water; in winter, they are seldom taken in less than 12 or 15 fathoms. Like other insects, they are much more active and alert in warm weather than in cold. In the water, they can run nimbly upon their legs or small claws; and, if alarmed, can spring, tail foremost, to a surprising distance, as swift as a bird can fly. The fishermen can see them pass about 30 feet; and, by the swiftness of their motion, suppose they may go much further. Athenaeus remarks this circumstance, and says, that "the incurvated lobsters will spring with the activity of dolphins." Their eyes are raised upon moveable bases, which enables them to see readily every way. When frightened, they will spring from a considerable distance to their hold in the rock, and, what is not less surprising than true, will throw themselves into their hold in that manner through an entrance barely sufficient for their bodies to pass.
2. The trigonous, or plated lobster, with a pyramidal spiny snout; thorax elegantly plated, each plate marked near its junction with short striae; claws much longer than the body, thick, echinated, and tuberculated; the upper fang trifid; only three legs spiny on their sides; tail broad. The largest of this species is about six inches long. It inhabits the coasts of Anglesea, under stones and fucoid. It is very active; and, if taken, flaps its tail against the body with much violence and noise.
3. The astacus, or craw-fish, with a projecting snout slightly Cancer. slightly serrated on the sides; a smooth thorax; back smooth, with two small spines on each side; claws large, beset with small tubercles; two first pair of legs clawed, the next subulated; tail consisting of five joints; the caudal fins rounded. It inhabits many of the rivers in England, lodged in holes which they form in the clayey banks. Cardan says, that this species indicates the goodness of water; for in the best water they are boiled into the reddest colour.
4. The serratus, or prawn, with a long serrated snout bending upwards; three pair of very long filiform feelers; claws small, furnished with two fangs; smooth thorax; five joints to the tail; middle caudal fin subulated, two outmost flat and rounded. It is frequent in several shores among loose stones; sometimes found at sea, and taken on the surface over 30 fathoms depth of water; cinereous when fresh, of a fine red when boiled.
5. The crangon, or shrimp, with long slender feelers, and between them two projecting laminae; claws with a single, hooked, moveable fang; three pair of legs; seven joints in the tail; the middle caudal fin subulated, the four others rounded and fringed, a spine on the exterior side of each of the outmost. It inhabits the shores of Britain in vast quantities, and is the most delicious of the genus.
6. The squilla, with a snout like a prawn, but deeper and thinner; the feelers longer in proportion to the bulk; the sub-caudal fins rather larger; is, at full growth, not above half the bulk of the former.—It inhabits the coasts of Kent; and is sold in London under the name of the white shrimp, as it assumes that colour when boiled.
7. The atomos, or atom-lobster, with a slender body; filiform antennae; three pair of legs near the head; behind which are two pair of oval vesiculae; beyond are three pair of legs, and a slender tail between the last pair. It is very minute, and the help of the microscope is often necessary for its inspection.
8. The pullex, or flea-lobster, with five pair of legs, and two claws, imperfect; with 12 joints of the body. It is very common in fountains and rivulets; swims very swiftly in an incurved posture on its back; embraces and protects its young between the legs; does not leap.
9. The locust, or locust-lobster, with four antennae; two pair of imperfect claws; the first joint ovated; body consists of 14 joints, in which it differs from the former. It abounds, in summer, on the shores, beneath stones and algae; leaps about with vast agility.
10. The digenes, folder-crab, or hermit-crab, with rough claws; the left claw is the longest (this being the only difference between the digenes and bernardus); the legs are subulated, and serrated along the upper ridge; the tail naked and tender, and furnished with a hook by which it secures itself in its lodging. This species is parasitic; and inhabits the empty cavities of turbinated shells, changing its habitation according to its increase of growth from the small nerite to the large nubell. Nature denies it the strong covering behind, which it hath given to others of this class; and therefore directs it to take refuge in the deserted cases of other animals. They crawl very fast with the shell on their back; and at the approach of danger draw themselves within the shell, and, thrusting out the larger claw, will pinch very hard whatever molests them. Aristotle describes it very exactly under the name of ἀκριβίαν. By the moderns it is called the folder, from the idea of its dwelling in a tent; or the hermit, from retiring into a cell.
It is very diverting to observe this animal when wanting to change its shell. The little folder is seen busily parading the shore along that line of pebbles and shells which is formed by the extremest wave; still, however, dragging its old inconvenient habitation at its tail, unwilling to part with one shell, even though a troublesome appendage, till it can find another more convenient. It is seen stopping at one shell, turning it, and passing it by; going on to another, contemplating that for a while, and then slipping its tail from its old habitation to try on the new: this also is found to be inconvenient, and it quickly returns to its old shell again. In this manner it frequently changes, till at last it finds one light, roomy, and commodious; to this it adheres, though the shell be sometimes too large as to hide the body of the animal, claws and all. Yet it is not till after many trials, and many combats also, that the folder is thus completely equipped; for there is often a contest between two of them for some well-looking favourite shell for which they are rivals. They both endeavour to take possession; they strike with their claws, they bite each other, till the weaker is obliged to yield by giving up the object of dispute. It is then that the victor immediately takes possession, and parades it in his new conquest three or four times back and forward upon the strand before his envious antagonist. When this animal is taken, it sends forth a feeble cry, endeavouring to seize the enemy with its nippers; which if it fastens upon, it will sooner die than quit the grasp.
The hermit-crabs frequent mostly those parts of the sea-shores which are covered with shrubs and trees, producing various wild fruits on which they subsist; though they will also feed on the fragments of fish and other animal substances cast on shore. When roasted in the shell, they are esteemed delicate. The hermit-crab, hung in the air, dissolves into a kind of oil, which speedily cures the rheumatism, if rubbed upon the part.
11. The vocans, or sand-crab, is but of a small size; its colour light brown, or dusty white. It has eight legs, and two claws, one of which is double the size of the other; these claws serve both to defend and to feed themselves with. The head has two square holes, which are receptacles for its eyes; out of which it thrusts them, and draws them in again at pleasure. Their abode is only on the sandy shores of Ilatha, and many others of the Bahama islands. They run very fast, and retreat from danger into little holes they make in the sand.
12. The grapsus, or red mottled crab, hath a round body, the legs longer and larger than in other kinds; the claws red; except which, the whole is mottled in a beautiful manner with red and white. These crabs inhabit the rocks hanging over the sea; they are the nimblest of all others, and run with surprising agility along the upright side of a rock, and even under the rocks that hang horizontally below the water. This they are often necessitated to do for escaping the assaults of rapacious birds that pursue them. These crabs never never go to land; but frequent mostly those parts of the promontories and islands of rocks in and near the sea, where, by the continual and violent agitation of the waves against the rocks, they are always wet, continually receiving the spray of the sea, which often washes them into it; but they instantly return to the rock again, not being able to live under water, and yet requiring more of that element than any of the crustaceous kinds that are not fish.
13. The granulatus, or rough-hulled crab: these crabs are pretty large, and are commonly taken from the bottom of the sea in shallow water; the legs are small in proportion to the body; the two claws are remarkably large and flat. The whole shell is covered over with innumerable little tubercles like thagreen: the colour is brown, variously stained with purple.
14. The cancer erythropus, or red-claw crab, is of a small size, and brown colour; it hath two claws of unequal bigness, red at the ends; and eight legs, which seem of less use to them than in other crabs; for when on the ground, they crawl with slow pace, dragging their bodies along; but they are mostly seen grasping with their claws, and hanging to some sea-plant, or other marine substance.
15. The pium, or pea-crab, with rounded and smooth thorax, entire and blunt; with a tail of the size of the body, which commonly is the bulk of a pea. It inhabits the mussels, and has unjustly acquired the repute of being poisonous. The swelling after eating of mussels is wholly constitutional; for one that is affected by it, hundreds remain uninjured. Crabs either of this kind, or allied to them, the ancients believed to have been the constant companions of the Pinnae, and other bivalves; which, being too stupid to perceive the approach of their prey, were warned of it by their vigilant friend. Oppian tells the fable prettily:
In clouded deeps below, the pinna hides, And through the silent paths obscurely glides; A stupid wretch, and void of thoughtful care, He forms no bait, nor lays the tempting snare; But the dull flaggard boasts a crab his friend, Whose busy eyes the coming prey attend. One room contains them, and the partners dwell Beneath the convex of one sloping shell; Deep in the watery vast the comrades rove, And mutual interest binds their constant love; That wiser friend the lucky juncture tells, When in the circuit of his gaping shells Fifth wand'ring enter; then the bearded guide Warns the dull mate, and pricks his tender side; He knows the hint, nor at the treatment grieves, But hugs th' advantage, and the pain forgives; His cloathing shells the pinna sudden joins, And 'twixt the pressing sides his prey confines: Thus fed by mutual aid, the friendly pair Divide their gains, and all the plunder share.
16. The manas, or common crab, with three notches on the front; five serrated teeth on each side; claws ovated; next joint toothed; hind feet subulated; dirty green colour; red when boiled. It inhabits all our shores; and lurks under the algae, or burrows under the sand. It is sold, and eaten by the poor of our capitals.
17. The pagurus, or black clawed crab, with a cre-
nated thorax; smooth body; quinquedentated front; smooth claws and black tips; hind feet subulated. It inhabits the rocky coasts; is the most delicious meat of any; casts its shell between Christmas and Easter. The tips of the claws of this species are used in medicine; intended to absorb acidities in the stomach and bowels.
18. The velutinus, or velvet crab, with the thorax quinquedentated; body covered with short, brown, velvet-like pile; claws covered with minute tubercles; small spines round the top of the second joint; hind legs broadly ovated.—This is among the species taken notice of by Aristotle on account of the broad feet, which, he says, assist them in swimming; as web-feet do the water-fowl. It inhabits the western coast of Anglesea.
19. The horridus, or horrid-crab, with a projecting bifurcated snout, the end diverging; body heart-shaped; with the claws and legs covered with long and very sharp spines.—It is a large species, and inhabits the rocks on the eastern coasts of Scotland. It is common to Norway and Scotland, as many of the marine animals and birds are.
20. The ruricola, land-crab, or violet-crab, with violet a smooth entire thorax, and the two last joints of the crab feet armed with spines. It inhabits the Bahama islands, as well as most lands between the tropics; and feeds upon vegetables.
These animals live not only in a kind of orderly society in their retreats in the mountains, but regularly once a year march down to the sea-side in a body of some millions at a time. As they multiply in great numbers, they choose the month of April or May to begin their expedition; and then fall out by thousands from the stumps of hollow trees, from the clefts of rocks, and from the holes which they dig for themselves under the surface of the earth. At that time the whole ground is covered with this band of adventurers; there is no setting down one's foot without treading upon them. The sea is their place of destination, and to that they direct their march with right-lined precision. No geometrician could fend them to their destined station by a shorter course; they neither turn to the right nor left, whatever obstacles intervene; and even if they meet with a house, they will attempt to scale the walls to keep the unbroken tenor of their way. But though this be the general order of their route, they, upon other occasions, are obliged to conform to the face of the country; and if it is intersected with rivers, they are then seen to wind along the course of the stream. The procession sets forward from the mountains with the regularity of an army under the guidance of an experienced commander. They are commonly divided into three battalions; of which the first consists of the strongest and boldest males, that, like pioneers, march forward to clear the route and face the greatest dangers. These are often obliged to halt for want of rain, and to go into the most convenient encampment till the weather changes. The main body of the army is composed of females, which never leave the mountains till the rain is set in for some time, and then descend in regular battalions, being formed into columns of 50 paces broad, and three miles deep, and so close that they almost cover the ground. Three or four days after this, the rear-guard follows, a frag- ging undisciplined tribe, consisting of males and females, but neither so robust nor so vigorous as the former. The night is their chief time of proceeding; but if it rains by day, they do not fail to profit by the occasion; and they continue to move forward in their slow uniform manner. When the sun shines and is hot upon the surface of the ground, they then make an universal halt, and wait till the cool of the evening. When they are terrified, they march back in a confused disorderly manner, holding up their nippers, with which they sometimes tear off a piece of the skin, and then leave the weapon where they inflicted the wound. They even try to intimidate their enemies; for they often clatter their nippers together, as if it were to threaten those that come to disturb them. But tho' they thus strive to be formidable to man, they are much more so to each other; for they are possessed of one most uncouth property, which is, that if any of them by accident is maimed in such a manner as to be incapable of proceeding, the rest fall upon and devour it on the spot, and then pursue their journey.
When, after a fatiguing march, and escaping a thousand dangers, (for they are sometimes three months in getting to the shore), they have arrived at their destined port, they prepare to cast their spawn. The peas are as yet within their bodies, and not excluded as is usual in animals of this kind, under the tail; for the creature waits for the benefit of sea-water to help the delivery. For this purpose the crab has no sooner reached the shore, than it eagerly goes to the edge of the water, and lets the waves wash over its body two or three times. This seems only a preparation for bringing their spawn to maturity; for, without farther delay, they withdraw to seek a lodging upon land; in the mean time the spawn grows larger, is excluded out of the body, and sticks to the barbs under the flap, or more properly the tail. This bunch is seen as big as an hen's egg, and exactly resembling the roes of herrings. In this state of pregnancy they once more seek the shore for the last time; and shaking off their spawn into the water, leave accident to bring it to maturity. At this time whole shoals of hungry fish are at the shore in expectation of this annual supply; the sea to a great distance seems black with them; and about two thirds of the crabs eggs are immediately devoured by these rapacious invaders. The eggs that escape are hatched under the sand; and, soon after, millions at a time of these little crabs are seen quitting the shore, and slowly travelling up to the mountains. The old ones, however, are not so active to return; they have become so feeble and lean, that they can hardly creep along, and the flesh at that time changes its colour. The most of them, therefore, are obliged to continue in the flat parts of the country till they recover, making holes in the earth, which they cover at the mouth with leaves and dirt, so that no air may enter. There they throw off their old shells, which they leave, as it were, quite whole; the place where they opened on the belly being unseen. At that time they are quite naked, and almost without motion for six days together, when they become so fat as to be delicious food. They have then under their stomachs four large white stones, which gradually decrease in proportion as the shell hardens, and, when they come to perfection, are not to be found. It is at that time that the animal is seen slowly making its way back; and all this is most commonly performed in the space of six weeks.
This animal, when possessed of its retreats in the mountains, is impregnable; for, only subsisting upon vegetables, it seldom ventures out; and its habitation being in the most inaccessible places, it remains for a great part of the season in perfect security. It is only when impelled by the desire of bringing forth its young, and when compelled to descend into the flat country, that it is taken. At that time the natives wait for its descent in eager expectation, and destroy thousands; but, disregarding their bodies, they only seek for that small spawn which lies on each side of the stomach within the shell, of about the thickness of a man's thumb. They are much more valuable upon their return after they have cast their shell; for, being covered with a skin resembling soft parchment, almost every part except the stomach may be eaten. They are taken in the holes by feeling for them with an instrument; they are sought after by night, when on their journey, by flambeaux. The infant the animal perceives itself attacked, it throws itself on its back, and with its claws pinches most terribly whatever it happens to fasten on. But the dexterous crab-catcher takes them by the hinder legs in such a manner that the nippers cannot touch him, and thus he throws them into his bag. Sometimes also they are caught when they take refuge in the bottoms of holes in rocks by the sea-side; by clapping a stick at the mouth of the hole, which prevents their getting out; and then soon after, the tide coming, enters the hole, and the animal is found, upon its retiring, drowned in its retreat.
These crabs are of various sizes, the largest about six inches wide; they walk side-ways like the sea-crab, and are shaped like them: some are black, some yellow, some red, and others variegated with red, white, and yellow mixed. Some of these are poisonous; and several people have died of eating of the crabs, particularly of the black kind. The light-coloured are reckoned best; and when full in flesh, are very well tasted. In some of the sugar islands they are eaten without danger; and are no small help to the negro slaves, who, on many of these islands, would fare very hard without them.
medicine, a roundish, unequal, hard, and livid tumour, generally seated in the glandulous parts of the body, supposed to be so called, because it appears at length with turgid veins shooting out from it, so as to resemble, as it is thought, the figure of a crab-fish; or, others say, because, like that fish, where it has once got, it is scarce possible to drive it away. See (the Index subjoined to) Medicine.
astronomy, one of the twelve signs, represented on the globe in the form of a crab, and thus marked (♋) in books. It is the fourth constellation in the starry zodiac, and that from which one quadrant of the ecliptic takes its denomination. The reason generally assigned for its name as well as figure, is a supposed resemblance which the sun's motion in this sign bears to the crab-fish. As the latter walks backwards, so the former, in this part of his course, begins to go backwards, or recede from us; though the dispo- disposition of stars in this sign is by others supposed to have given the first hint to the representation of a crab.
Tropic of Cancer, in astronomy, a lesser circle of the sphere parallel to the equator, and passing through the beginning of the sign Cancer.