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 abdominak 
segment. ‘I'he accessory plates to the peduncle of the external antenne 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 Bluwebacks, 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. 
* LassalGNE, Journal de Pharmacie, Vol. 6, p. 174. 
