374 BULLETIN 97, UNITED STATES NATIONAL MUSEUM. 



Color. Yellowish. 



Measurements. Length of carapace of male (17297) 31.7; width 

 of same 40.5 mm. 



Habits. The following notes were furnished by Mr. J. Fid Tris- 

 tan of Costa Rica : 



They live on the seashore whore they dig holes in the sand. Their yellowish 

 color is more or less confused with the color of the saml. The rising tide 

 entirely covers the holes with ,;;r.d; at low tide the crabs begin to come out 

 sideways, remaining on the ;Hlge of the holes and hiding very quickly at the 

 slightest noise. If anything falls near them they jump at it with extraordinary 

 rapidity, as a spider in its web, and try to secure It with their claws so as to 

 carry it off quickly to their holes. 



Range. Gulf of Fonseca, Salvador, to Chile; Galapagos Islands. 

 San Pablo, California (Mus. Comp. Zool.). Also said by Cano to 

 occur at Honolulu. 



Material examined. 



Gulf of Fonseca, Salvador (M. C. Z.). 



Corinto, Nicaragua (M. C. Z.). 



Boca del Rio Jesus M.iria, Costa Rica; April, 1905; P. Biolley and 

 J. F. Tristan; 1 female f 32312). 



Pigres, Costa Rica; Mar. 3, 1905; A. Zeledon; 3 females (43292). 



Taboga Island, Panama; June, 1914; J. Zetek; 5 males (48790). 



Panama: Mar. 15, 1888; Albatross; 1 female (22077). H. A. 

 Ward; 2 males (17297). 



Bahia, Ecuador; beach; Aug. 26, 1884; Dr. TV. H. Jones, U. S. 

 Navy; 9 males (13871). 



Manta, Ecuador; sandy beach; Aug. 28, 1884; Dr. TV. H. Jones. 

 U. S. Navy; 1 male (13872). 



Guayaquil, Ecuador; Dr. TV. H. Jones, U. S. Navy; 1 male, 1 fe- 

 male (14094). 



Peru ; 1906-1908 ; R. E. Coker : Las Vacas, near Capon ; on beach ; 

 Jan. 23, 1908; 3 males, 1 female (40457). Lobos de Afuera; beach; 

 Mar. 30; 1 male, 1 female (40456). Chimbote; Feb. 27; sand beach; 

 2 males, 1 female (40458). 



Chatham Island, Galapagos Islands; Albatross: Apr. 4, 1888; 1 

 female (22078). Jan. 8, 1905; 2 females (33163). 



Valparaiso, Chile; 2 young (M. C. Z.). 



Locality?; Albatross; 7 males, 6 females (22079). 



Genus UCA Leach. 



FIDDLER CRABS ; CALLING CRABS. 



Uca LEACH, Edin. Encyc., vol. 7, 1814. p. 430; type, U. una Leach, 1814= 

 U. lictcroclielos (Lamarck), 1801. RATHBUN, Proc. Biol. Soc. Wash- 

 ington, vol. 11, 1897, p. 154. 



Oelasimus LATREIT,LK, Nouv. Diet. Hist. Nat., vol. 12, 1817, p. 517; type 

 Q. maracoani (Latreille). 



