A GROUP OF CRUSTACEANS
1. Common Lobster. 2. Thornback Crab. 3. Land Crab. 4. Hermit Crab.
5. Barnacle. 6. Scorpion. 7. Antarctic Trilobite.
Crab.—In this class of Crustaceans the abdomen is small and folded under the anterior part of the body. Over two thousand species are known, differing greatly in size, shape, and in other respects. The great majority are marine, but there are a few which spend their entire life on land, only going to the water once a year to lay their eggs. The largest is the great spider crab of Japan, whose legs may stretch out a dozen feet. One species on the Atlantic coast is taken at molting time in great numbers and forms the favorite soft-shell crab of the table. The hermit crabs have the abdomen soft, and to protect this vulnerable part, they insert it in the shell of some dead snail, and carry this about with them wherever they go.
Barnacle.—A family of marine crustaceous animals enveloped by a mantle and shell, composed of five principal valves and several smaller pieces, joined together by a membrane attached to their circumference. They are furnished with a long, flexible, fleshy stalk, provided with muscles, by which they attach themselves to ships’ bottoms, submerged timber, etc. They feed on small marine animals, brought within their reach by the water and secured by their tentacula. Some of the larger species are edible.
Crayfish.—Small, fresh-water crustaceans, which resemble the lobsters in appearance. They usually live in burrows in the banks or bottoms of streams and feed on decaying animal matter. In Europe they form a considerable element in the food supply and are bred in ponds. A large number of species occur in the United States, and are always to be found in the larger markets.
Lobster.—The most important of the crustaceans. One species occurs on our east coast, another on the coast of northern Europe. The body is divided into two regions, the anterior bearing, besides the parts used in taking food, a pair of large pincers and four pairs of walking feet. At the front of the head are two pairs of feelers, which are sensory, and a pair of eyes on the ends of short stalks. The lobsters are fond of decaying fish and are among the scavengers of the sea. They are caught in large traps, called lobster pots, made out of lath and baited with decaying fish. The annual catch on the New England coast is estimated at about thirty million pounds, the average weight of a lobster being between two and three pounds. Farther south on our east coast, in California and the Mediterranean a different animal is called lobster.
Prawn.—Crustaceans nearly allied to shrimps and lobsters, but not exclusively marine. They vary in size from a couple of inches to over a foot in some tropical forms. Many of them are semi-transparent, and exhibit very fine colors. On the approach of night they change to a beautiful blue, but the meaning of this “sunset” coloration is not fully understood. Some of the deep-sea prawns are blind; others possess enormous eyes, and many emit a phosphorescent light. They may be caught in putting nets or in osier baskets, like those used for trapping lobsters. They are esteemed for eating even more highly than the shrimp.
Shrimps.—Small crustaceans allied to the lobster, most of them inhabitants of the sea. In many countries they form an important part of the diet, but with us they are little used with the exception of one or two southern species which are used as a basis for shrimp salad. Shrimps are very abundant off our coast and could be made an important fishery.