26 NEW-YORK FAUNA — CRUSTACEA. 
tending nearly to the posterior margin of the thorax. Eyes sessile, and resting upon the con- 
cave surface of the peduncle of the interior antenna. Outer antenne nearly equalling the 
total length, and furnished with an oblong tapering plate, truncate at the tip, nearly as long 
as the internal antenna, with a raised external border, and ciliate on the internal margin with 
long hairs. Anterior feet with a slender curved claw, opposable to a sharp prominent spine. 
Second and third pair of feet exceedingly slender ; the remainder more robust, and all with 
simple acute tips. Middle caudal plate simple, conic, concave beneath ; outer plates oblong- 
oval, margined with hairs. 
Color, very pale greenish, frequently translucent ; the basal plates of the external antenna, 
and the caudal plates, punctate with brown. 
Length, 1°5-—1°75. 
This is a lively little animal, and known under the popular name of Bait Shrimp, being used 
exclusively for bait. M. Edwards observes that this differs very little from the C. vulgaris, or 
Common Shrimp of Europe, but admits that it may probably be anew species. In his edition 
of Lamarck’s Animauax sans vertébres, published subsequently to his work on the Crustacea, 
he passes it over in silence. Dr. Gould considers the two species as identical ; there appears, 
however, to be a notable difference in the shape of the basillary plates of the external antenne. 
In many parts of Europe, the Shrimp is eaten in great quantities. Our species has a wide 
geographical range, being found from Florida to the Arctic ocean. 
(EXTRA-LIMITAL.) 
C. boreas. (Puirps, Voyage, p. 194. Mutxer, Zool. Dan. Vol. 4, pl. 182, fig. 1.) Shell rough, armed 
along the medial line witha trifid crest. The plate of the external antenne short and very wide. 
Second and third pair of feet filiform ; feet of the two last pair very large. Medial plate of the tail 
with seven spines. Color, variegated with reddish. Length, 5-0—7:0. Stomachs of Cod-fish. 
Coast of Massachusetts. 
Genus Atpueus, Fabricius. Antenne arranged in two series, the internal above the external. First 
and second pair of feet didactyle. Hands of the first pair large and unequal; the three last 
pair monodactyle. Shield advanced above the eyes. Inhabiting the seas of warm climates. 
A. helerochelis. (Say, loc.cit. Vol. 1, p. 243.) Rostrum simple, spiniform, acute, carinate in the middle. 
Shield smooth, without spines. Larger hand di formed, compressed, abruptly constricted near the 
fingers on each edge. Culor, green, with small brownish spots; hand beneath white. Length, 
1-5. Florida, South-Carolina. 
A, minus. (Ip. loc. cit) Rostrum and shield over the eye, forming three spines in front, Larger 
hand not compressed, inflated. External jaw-feet obtuse at point, and crowned with spines. Color: 
Large hand white, the tip red, banded near the bases of the fingers with white in the female; white 
tipped with green in the male. Length, 0°8. South-Caroina and Florida. 
