172 BULLETIN 97, UNITED STATES NATIONAL MUSEUM. 



the right chela and right legs, and probably the last left leg, are in 

 process of regeneration. 



Measurements. — Female (paratype), length of carapace 5.8, Avidth 

 of same 8.2 mm. Male (49247), length of carapace 4.6, width of 

 same 6.2 mm. 



Range. — Departure Bay, British Columbia, to Ensenada, Lower 

 California. 



Sj^ecimens examined. — 



Departure Bay. British Columbia: George W. Taylor; 1 female 

 (39130). 



Friday Harbor, Washington: in Mya arenaria; July 1, 1916; 

 Evelyn D. Way; 1 male, 1 female (49951). 



Puget Sound; Aug., 1908: 3 males, 3 females, ovig. (Stanford 

 Univ.). 



Puget Sound, near Tacoma, Washington ; 1907 ; 2 males, 2 females 

 (1 ovig.), (Stanford Univ.). 



Oyster Bay. Washington, from stomach of BufRehead {(Hiari- 

 tonetta albeola) \ Dec. 4, 1914; 1 female (Biol. Survey Coll., U. S. 

 Dept. of Agr.). 



Middle San Francisco Bay; 7-4 fathoms; large and small angular 

 rock fragments; temp. 12.01° C. ; Apr. 16, 1912; station 5775a; 

 steamer Albatross; 1 male (49247). 



Ensenada, Lower California: C. R. Orcutt; 3 females (holotype 

 and paratypes) and fragment of male (17497). 



Genus OPISTHOPUS Rathbun. 



Opisthopns Rathbun, Proc. U. S. Nat. Mus., vol. 16, 1893, p. 251; type, 0. 

 transversus Rathbun. 



Carapace subquadrilateral. a little wider than long, firm, harder 

 in male than in female, smooth: regions not defined; antero-lateral 

 niargins arcuate; front rounding down toward the epistome. Outer 

 maxillipeds Avith ischium Mell developed and Avell defined, but partly 

 fused with the merus; merus wide, palpus 3-jointed. the last joint 

 articulated near the proximal end of the inner side of the penulti- 

 mate joint. Ambulatory legs similar and differing little in size, 

 second longest. 



Perhaps should be united with Pinnaxodes. 



Ivnown only from the typical species. 



