of the Pacific Shores of North America. 481 
upper surface between the eyes is depressed, with a shallow 
median groove. Ocular peduncles broad; eyes small Su- 
perior margin of orbit somewhat concave. External anten- 
næ one and a half times as long as the carapax; flagella 
with few setze, some of which are twice as long as the 
width of the flagellum. Anterior feet very large and broad; 
margins smooth ; carpus scabrous on its infero-exterior sur- 
face, and conspicuously granulated above, along the slightly 
elevated ridge forming its outer margin, which terminates 
anteriorly in a tooth. The surface of the carpus near its 
somewhat projecting, rounded, postero-interior angle, is also 
granulated. Pincers smooth, with somewhat hooked ex- 
tremities, Second, third, and fourth pairs of feet of mod- 
erate size; fourth joint with a slight ridge along the middle 
of the upper surface ; fifth joint and tarsus provided with 
tufts of hair, which are most conspicuous in the fourth pair 
of feet, in which pair the fourth joint also has sometimes 
one or two small tufts near its extremity. 
Color, dark purplish-red. Length of carapax in a male 
Specimen, 0.85 ; breadth, 0.80 ; length of hand, 1.47 ; breadth, 
64 inch. 
Its affinities are with P. valida, violacea, and granulosa. 
It is easily distinguished from the preceding species by the 
8mooth anterior margin of its carpus. 
It is very common among the rocks of the Californian 
coast, preferring an open shore, with clear water. Itis lit- 
toral in its habits, and is usually found at about half- 
tide mark. It was taken at the Farallones and at San 
Luis Obispo by Lieut. Trowbridge; at Monterey by Mr. 
Taylor. 
Mus. Bost. Soc.; Phil. Acad.; Smithsonian, 
JOURNAL B. s, N. H. 
