In these animals the body is compressed and the carapace is not hard. The abdomen is very large in proportion to the cephalothorax, and has a peculiar bend. The rostrum is often longer than the thorax. The eye-stalks, antennæ, and legs sometimes attain extraordinary length, and the chelæ (claws) are not always on the first pair of legs. In some species chelæ are on two or three pairs of the legs. Above the antennæ are expanded antennal scales, which, together with the long bases of the antennules and very prominent eye-stalks, make the head a broad and conspicuous feature. The difference between shrimps and prawns is not very well defined, the small individuals seeming to be generally called shrimps, the larger full-grown ones prawns. [pg260] Prawns are known as /crevettes/ in France and as /Garnelen/ in Germany, where they are largely used as food. In the United States the shrimp-fishery is an industry of the South. On the California coast the fisheries are very extensive and are monopolized by the Chinese.
^P. setiferus.^ This species is about six inches in length when full-grown. A ridge or crest extends along the center of the carapace, and terminates in a long, pointed, toothed rostrum, the teeth being fringed with hair on the inner side. The antennæ are a foot or more in length; there are chelæ on the first three pairs of thoracic feet; the swimming-feet and lateral margins of the segments of the abdomen are fringed with hair; and the caudal appendages are longer than the telson. It ranges from Virginia southward, and is very abundant on the shores of the Southern States, where it is gathered for the markets. The large ones are known as prawns and the small ones as shrimps.
^P. brasiliensis.^ This species is associated with /P. setiferus/, and, although not so abundant, forms a part of the shrimp-supply in the fisheries. It differs from the former in having a groove on each side of the ridge which runs through the center and whole length of the carapace. The first three pairs of feet are chelated. This shrimp is found as far north as Long Island, and often in brackish water, or even where the water is quite fresh.
^P. vulgaris (Palæmon vulgaris).^ Average size one half of an inch in length; body translucent, almost colorless, irregularly spotted; rostrum as long as carapace and toothed on the upper edge. It is found among eel-grass in brackish water, and also in pools and ditches on muddy shores from Massachusetts Bay to Florida. Commonly known as prawns.