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- 

 nae one and a half times as long as the carapax ; flagella 

 with few setae, 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, 

 0.64 inch. 



Its affinities are with P. valida, violacea, and granulosa. 

 It is easily distinguished from the preceding species by the 

 smooth anterior margin of its carpus. 



It is very common among the rocks of the Californian 

 coast, preferring an open shore, with clear water. It is 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. 62 



