ORDER DECAPODA — PLATYCARCINUS. 7 
separated from this a closely allied species, which he thinks has been confounded by Say 
himself with the preceding, supposing one to be the male and the other the female. It ap- 
pears to have a wide geographical range, for Mr. Randall (Jour. Acad. Nat. Sc. Vol. 8) 
has noticed it on the northwest coast of North America. 
PLATYCARCINUS SAYI. 
Cancer irroratus. Say, Jour. Acad. Nat. Sc. partly, Vol. 1, p. 60, pl. 4, fig. 2. 
Cc. sayi. Gou tp, Invertebrata of Massachusetts, p. 322. 
Description. Shield smooth, less convex and more angular at the sides than in the preceding. 
The teeth on the antero-lateral margins nine, pointed, smooth, not denticulated. Legs longer 
in proportion than the preceding; the thighs of the second and third pair greatly exceeding 
the margin of the shield. Lines on the external part of the hand not conspicuously granu- 
lated. Abdominal segment of the male broader than in the preceding species. 
Color, yellow, dotted with dark purplish brown. Finger and thumb scarcely dark colored ; 
bend of the wrist and inner face of the hand bright rose-red. 
Length, 2°75. ‘Transverse diameter, 4°0. 
This species was first separated from the preceding by Drs. Gould and Binney, and has 
been observed on this coast. According to Dr. Gould, it is common on rocky bottoms, and 
is brought in considerable numbers to market. 
GENUS PILUMNUS. Leach. 
Shield arched in front. Feet of the first pair unequal. The second joint of the external an- 
tennz lodging in the internal canthus of the orbit, and the antenne extending beyond the 
margin of the shield. In other respects, resembling Xanruus. 
PILUMNUS HARRISI. 
PLATE VII. FIG, 15. 
Pilumnus harrisi. Govutp, Invertebrata of Mass. p. 326. 
Description. Shield quadrilateral, narrowed backwards, rounded before, rectilinear behind 
and at the sides. Three triangular teeth at the sides; eyes distant; orbits oval, witha fissure 
over the centre; front divided by a fissure into two lobes. Surface very minutely granulated, 
and hispid with very short hairs, which entangle the dirt: there are three or four broken 
series of curved transverse lines or ridges rising into little crests. Limbs slender, cylindrical. 
Carpus with a projecting angle in front. Hands robust, smooth, and with a double line along 
