16 NEW-YORK FAUNA — CRUSTACEA. 
Front entire : third joint of the anterior pair serrate on the inner edge, and four-toothed at the 
tip. Hands large, granulate beneath. Carpus with an obtuse spine. 'Tarsi short and spi- 
nous beneath. 
Color, variable, but most usually brownish, mottled with ash. Eyes reddish brown. 
Length, 0°3. ‘Transverse diameter, 0°2. 
This little species is usually found upon seaweed, or the larger marine animals in the 
ocean. It has been noticed on seaweed off the harbor of New-York. But a single species 
is yet known. 
GENUS PLAGUSIA. Latreille. 
General form of the preceding, but the internal antenne are short, vertical, and moving in 
deep cavities which are open above, and formed in the substance of the shield. Mouth 
nearly closed in front. 
PLAGUSIA SAYI. 
Plagusia depressus. Say, Jour. Acad. Nat. Sc. Vol. 1, p. 100. 
Description. Shield with numerous distant punctures, having the appearance of being 
covered with scales, each of which is bounded before by a line of impressed points furnish- 
ing hairs. Sides of the shield with three serrate teeth; the posterior canthus of the eye 
elevated into a tooth, with a small tubercle within its base. Carpus with a depressed spine 
within, which is emarginate at tip. Hands granulate above, with small tubercles and two 
impressed lines. 'Tarsi with a double line of movable spines beneath; tip of the preceding 
joint about five-spined beneath. 
Color, variegated ; tibia darker, spotted; beneath white, immaculate. 
Mr. Say received this species from the Gulf stream, and considered it as synonimous with 
the P. depressa from the Indian ocean and coast of China. From this it is distinguished by 
the hairy tubercles on its shield. I agree with M. Milne-Edwards in considering it more 
allied to P. sguamosa from the Red sea and Indian ocean. ‘This latter, however, is charac- 
terized by its shield bristling with elevated tubercles, each of which is furnished with a series 
of stiff hairs directed forward, and resembling scales. It may provisionally, until a direct 
comparison is made, be considered as a new species, taking of course the name of its learned 
and indefatigable discoverer 
