I have no intention of describing the whole members of the crustacea; they are much too numerous to admit of that, ranging as they do from the comparatively giant-like crab and lobster down to the millions of minute insects which at some places confer a phosphorescent appearance on the waters of the sea. My limits will necessarily confine me to a few of the principal members of the family—the edible crustacea, in fact; and these I shall endeavour to speak about in such plain language as I think my readers will understand, leaving out as much of the fashionable “scientific slang” as I possibly can.
The more we study the varied crustacea of the British shores, the more we are struck with their wonderful formation, and the peculiar habits of their members. I once heard a clergyman at a lecture describe a lobster in brief but fitting terms as a standing romance of the sea—an animal whose clothing is a shell, which it casts away once a year in order that it may put on a larger suit—an animal whose flesh is in its tail and legs, and whose hair is in the inside of its breast, whose stomach is in its head, and which is changed every year for a new one, and which new one begins its life by devouring the old! an animal which carries its eggs within its body till they become fruitful, and then carries them outwardly under its tail; an animal which can throw off its legs when they become troublesome, and can in a brief time replace them with others; and lastly, an animal with very sharp eyes placed in movable horns. The picture is not at all overdrawn. It is a wondrous creature this lobster, and I may be allowed a brief space in which to describe the curious provision of nature which allows for an increase of growth, or provides for the renewal of a broken limb, and which applies generally to the edible crustacea.
The habits of the principal crustacea are now pretty well understood, and their mode of growth is so peculiar as to render a close inspection of their habits a most interesting study. As has been stated, a good-sized lobster will yield about 20,000 eggs, and these are hatched, being so nearly ripe before they are abandoned by the mother, with great rapidity—it is said in forty-eight hours—and grow quickly, although the young lobster passes through many changes before it is fit to be presented at table. During the early periods of growth it casts its shell frequently. This wonderful provision for an increase of size in the lobster has been minutely studied during its period of moulting. Mr. Jonathan Couch says the additional size which is gained at each period of exuviation is perfectly surprising, and it is wonderful to see the complete covering of the animal cast off like a suit of old clothes, while it hides, naked and soft, in a convenient hole, awaiting the growth of its new crust. In fact, it is difficult to believe that the great soft animal ever inhabited the cast-off habitation which is lying beside it, because the lobster looks, and really is, so much larger. The lobster, crab, etc., change their shells about every six weeks during the first year of their age, every two months during the second year, and then the changing of the shell becomes less frequent, being reduced to four times a year. It is supposed that this animal becomes reproductive at the age of five years. In France the lobster-fishery is to some extent “regulated.” A close-time exists, and size is the one element of capture that is most studied. All the small lobsters are thrown back to the water. There is no difficulty in observing the process of exuviation. A friend of mine had a crab which moulted in a small crystal basin. I presume that at some period in the life of the crab or lobster growth will cease, and the annual moulting become unnecessary; at any rate, I have seen crabs and other crustaceans taken from an island in the Firth of Forth which were covered with parasites evidently two or three years old.
To describe minutely the exuviation of a lobster, crab, or shrimp would in itself form an interesting chapter of this work, and it is only of late years that many points of the process have been witnessed and for the first time described. Not long ago, for instance, it was doubtful whether or not the hermit-crabs (Anomoura) shed their skin; and, that fact being settled, it became a question whether they shed the skin of their tail! There was a considerable amount of controversy on this delicate point, till the “strange and unexpected discovery” was made by Mr. Harper. That gentleman was fortunate enough to catch a hermit-crab in the very act, and was able to secure the caudal appendage which had just been thrown off. Other matters of controversy have been instituted in reference to the growth of various members of the crustacea; indeed, the young of the crab in an early stage have before now been described by naturalists as distinct species, so great is the metamorphosis they undergo before they assume their final shape—just as the sprat in good time changes in all probability to the herring. Another point of controversy at one period existed in reference to the power of crustaceans to replace their broken limbs, or occasionally to dispense at their own good pleasure with a limb, when it is out of order, with the absolute certainty of replacing it.
When the female crustacea retire in order to undergo their exuviation they are watched, or rather guarded, by the males; and if one male be taken away, in a short time another will be found to have taken his place. I do not think there is any particular season for moulting; the period differs in different places, according to the temperature of the water and other circumstances, so that we might have shell-fish (and white-fish too) all the year round were a little attention paid to the different seasons of exuviation and egg-laying.
The mode in which a hen lobster lays her eggs is curious: she lodges a quantity of them under her tail, and bears them about for a considerable period; indeed, till they are so nearly hatched as only to require a very brief time to mature them. When the eggs are first exuded from the ovary they are very small, but before they are committed to the sand or water they increase considerably in size and become as large as good-sized shot. Lobsters may be found with eggs, or “in berry” as it is called, all the year round; and when the hen is in process of depositing her eggs she is not good for food, the flesh being poor, watery, and destitute of flavour.
When the British crustacea are in their soft state they are not considered as being good for food; but, curiously enough, the land-crabs are most esteemed while in that condition. The epicure who has not tasted “soft crabs” should hasten to make himself acquainted with one of the most delicious luxuries of the table. The eccentric land-crab, which lives far inland among the rocks, or in the clefts of trees, or burrows in holes in the earth, makes in the spring-time an annual pilgrimage to the sea in order to deposit its spawn, and the young, guided by an unerring instinct, return to the land in order to live in the rocks or burrow in the earth like their progenitors. In the fish-world we have something nearly akin to this. We have the salmon, that spends one half its life in the sea, and the other half in the fresh water; it proceeds to the sea to attain size and strength, and returns to the river in order to perpetuate its kind. The eel, again, just does the reverse of all this: it goes down to the sea to spawn, and then proceeds up the river to live; and at certain seasons it may be seen in myriad quantities making its way up stream. The march of the land-crabs is a singular and interesting sight: they congregate into one great army, and travel in two or three divisions, generally by night, to the sea; they proceed straight forward, and seldom deviate from their path unless to avoid crossing a river. These marching crabs eat up all the luxuriant vegetation on their route: their path is marked by desolation. The moment they arrive at the water the operation of spawning is commenced by allowing the waves to wash gently over their bodies. A few days of this kind of bathing assists the process of oviposition, and knots of spawn similar to lumps of herring-roe are gradually washed into the water, which in a short time finishes the operation. Countless thousands of these eggs are annually devoured by various fishes and monsters of the deep that lie in wait for them during the spawning season. After their brief seaside sojourn, the old crabs undergo their moult, and at this period thousands of them sicken and die, and large numbers of them are captured for table use, soft crabs being highly esteemed by all lovers of good things. By the time they have recovered from their moult the army of juveniles from the seaside begins to make its appearance in order to join the old stock in the mountains; and thus the legion of land-crabs is annually recruited by a fresh batch, which in their turn perform the annual migration to the sea much as their parents have done before them.
Before leaving the crabs and lobsters, it is worthy of remark that an experienced dealer can tell at once the locality whence any particular lobster is obtained—whether from the west of Ireland, the Orkney Islands, or the coast of Brittany. The shelly inhabitants of different localities are distinctly marked. Indeed fish are peculiarly local in their habits, although the vulgar idea has hitherto been that all kinds of sea animals herd indiscriminately together; that the crab and the lobster crept about the bottom rocks, whilst the waving skate or the swaggering lingfish dashed about in mid-water, the prowling “dogs” busily preying on the shoals of herring supposed to be swimming near; the brilliant shrimp flashing through the crowd like a meteor, the elegant saithe keeping them company; the whole being overshadowed by a few whales, and kept in awe by a dozen or so of sharks! Nothing can be more different than the reality of the water-world, which is colonised quite as systematically as the earth. Particular shoals of herring, for instance, gather off particular counties; the Lochfyne herring, as I have mentioned in the account of the herring-fishery, differs from the herring of the Caithness coast or that of the Firth of Forth; and any ’cute fishmonger can tell a Tweed salmon from a Tay one. The herring at certain periods move in gigantic shoals, the chief members of the Gadidæ congregate on vast sandbanks, and the whales occasionally roam about in schools; while the Pleuronectidæ occupy sandy places in the bottom of the sea. We have all heard of the great cod-banks of Newfoundland, of the fish community at Rockall; then is there not the Nymph Bank, near Dublin, celebrated for its haddocks? have we not also the Faroe fishing-ground, the Dogger Bank, and other places with a numerous fish population? There are wonderful diversities of life in the bosom of the deep; and there is beautiful scenery of hill and plain, vegetable and rock, and mountain and valley. There are shallows and depths suited to different aspects of life, and there is life of all kinds teeming in that mighty world of waters, and the fishes live
“A cold sweet silver life, wrapped in round waves,
Quickened with touches of transporting fear.”