24 NEW-YORK FAUNA — CRUSTACEA. 



a small spine on the anterior edge of the thorax. The rostrum is slightly furrowed on its 

 dorsal surface, and a linear furrow extends from it along the medial line to the first abdominal 

 segment. The accessory plates to the peduncle of the external antennae spinous ; the supe- 

 rior with a ciliate lamella. The last abdominal segment with a pencil of hairs on its external 

 angle, and occasionally another on each side of its posterior margin ; a single central spine 

 on the under side of the second, third, fourth and fifth abdominal rings. The caudal plates 

 all distinctly pencilled behind ; the first segment of the external one denticulate ; the central 

 plate rounded behind, with a spine on each side, which disappears in older individuals. 

 Hands compressed, for the most part unequal, owing to their having been casually detached 

 and renewed at different periods ; they have from five to nine spines on the inner edge, a 

 rounded tubercle on the upper or inner surface near the joints of the pincers, and a small 

 blunt spine on the superior and posterior surface of the hand. Carpus as in the European 

 lobster, with five spinous tubercles above and another beneath. 



Color, olivaceous green above, and in very old individuals verging to deep blackish green ; 

 darker spots and blotches over the body, hands and feet, spines and tubercles ; sides of the 

 thorax and of the abdominal segments, under side of the hands and the caudal hairs brick red. 



Length of the body, 12-0-24-0. Weight, 2- 10 lbs. 



The Common Lobster is well known, although it has not until recently been well distin- 

 guished from the Lobster of Europe. Ours, however, attains a greater size, and is perhaps 

 the largest species yet known among the Crustacea. The average weight may be stated at 

 about four pounds, but I have frequently seen them of the weight of fifteen to twenty pounds. 

 The largest I have heard of, was sold in the Fulton market, and weighed, as I am credibly 

 informed, thirty-five pounds. They are common in our markets during the whole year, but 

 more especially during the summer, when they are most highly relished, selling at from four 

 to eight cents per pound. The smaller ones are derived from the rocky shores of the East 

 river and Long-island sound. The larger individuals are brought to us alive from Fisher- 

 island sound and the rocky coasts north of Cape Cod. Fishermen suppose the small lobster 

 to be a different species, but without any foundation. 



There is a variety of the Lobster, termed Bluebacks, on account of their dark bluish color. 

 They are derived from the coast about Cape Cod, have comparatively thin shells, and are 

 highly prized by epicures ; they are seen chiefly at the commencement of the lobster season 

 in the early part of May. In June, 1840, I saw in the Fulton market a lobster which was' 

 of two colors, distinctly separated by a medial line from the tip of the rostrum to the middle 

 extremity of the plate of the tail. On one side the body and all the members were of a light 

 sky blue, and the other of the usual olivaceous green. It was doubtless occasioned by some 

 morbid change in the condition of the animal. The change of color which takes place when 

 this and several other Crustacea (but not all) are placed in boiling water, is owing to a peculiar 

 pigment* in the shell, which is usually brownish or greenish, but which changes to red at the 

 temperature of about 190° Fahrenheit, and also by the action of acids and alcohol. 



* Lassaigne, Journal de Phurmaci*, Vol. 6, p. 174. 



