THE GKAPSOID CKABS OF AMERICA. 73 



rounded. Orbits and eves oval, hidden from dorsal view. A large 

 prominent tubercle at posterior end of basal joint of antenna. 



Propodus of endognath distally rounded, dactylus small, attached 

 on inner portion of extremity of propodus. 



Chelipeds elongate, manus slightly compressed and increasing dis- 

 tally; immovable finger slightly deflexed, swollen in basal half; fin- 

 gers fitting together when closed, tips curved and crossing each other. 



Legs slender, second longest, third next, fourth shortest; dactyli 

 nearly straight, except that of second leg, which is twice as long as 

 of other legs, and nearly equaling its propodus. 



Abdomen unusually large. 



Measurements. Female (17467), length of carapace 9, width of 

 same 12.2 mm. 



Habitat. In oysters (Lockington) and mussels. 



Range. Gulf of California at Angeles Bay (type-locality) and 

 San Josef Island. 



Material examined. 



San Josef Island, Gulf of California, Mexico; Mar. 16, 1889; 5 

 females (3 ovig.) (17467). 



Angeles Bay, Gulf of California ; in Modiola copax; 4 females (3 

 ovig.) (Univ. Cal.). 



PINNOTHERES LITHODOMI Smith. 



Pinnotheres lithodomi SMITH, Trans. Connecticut Acad. Arts and ScL, 

 vol. 2, 1870, p. 169 (type-locality, Pearl Islands, Bay of Panama, in 

 Litlwdomus aristatus Forbes and Hanley; type in Peabody Mus. 

 Yale Univ.). 



Diagnosis. Merus of maxillipeds broadest at distal extremity, 

 sides nearly straight. Legs very slender; dactyli slightly curved, 

 third longest, second next, first and fourth subequal. 



Description of female. Dorsal surface of carapace smooth and 

 naked. Merus of outer maxillipeds broadest at distal extremity, both 

 margins nearly straight. Chelipeds equal, smooth and naked; hands 

 cylindrical; fingers short, nearly straight, tips slightly hooked by 

 each other, prehensile edge of dactylus armed, near base, with a small 

 tooth which fits a slight excavation in propodal finger. 



Legs very slender and wholly naked except dactyli; dactylus of 

 first leg very short and only slightly curved, of second leg consider- 

 ably longer than in first and nearly straight, of third leg very long, 

 nearly as long as propodi, slender and slightly curved; of last leg 

 about as long as second and ciliated along posterior edges. (After 

 Smith.) 



Measurement. Width of carapace about 4 mm. 



Habitat. In Lithophaga aristatus, a boring mollusk. 



