THE CANCROID CRABS OF AMERICA 519 



in a triangle behind it; two of the largest are on the hepatic region 

 and smaller ones are scattered on the branchial and posterior regions. 

 Median lobes of front almost perpendicular, separated by a deep, 

 acutely triangular sinus, anterior margins oblique, arcuate, and 

 slightly denticulate; the small lateral lobes are minute teeth or 

 tubercles. Upper margin of orbit armed with three small pointed 

 teeth, the outer one forming the external angle. Antero-lateral 

 margin armed with three long, triangular teeth which are separated 

 from the angle of the orbit by a broad shallow sinus below which 

 there is a slender subhepatic tubercle. Lower margin of orbit 

 broken by a deep sinus, the inner lobe prominent and usually some- 

 what bituberculate at tip, outer lobe armed along the margin with 

 three or four small tubercles; external hiatus well marked. Inferior 

 orbital region with a few scattered granules. An oblique line of 8 

 or 10 small tubercles on the subbranchial region terminating just 

 behind the posterior tooth of the antero-lateral margin. 



Chelipeds slightly unequal, carpus armed with a strong spine on 

 the inner edge and a few scattered tubercles on the upper surface, 

 hand tuberculate above and externally, the major palm with a naked 

 and smooth space on the lower edge at base of finger; fingers smooth, 

 striate and dark brown, the color not spreading on palm. Legs 

 armed with a few scattered sharp granules on upper side. 



Measurements. — Male, cotype (Panama), length of carapace 1L4, 

 width of same 15 mm. Female (60225), length of carapace 6.6, 

 width of same 9.5, fronto-orbital width 6, width of front 2.7 mm. 



Range. — Panama; Ecuador; Peru. 



Material examined. — Panama; Capt. J. M. Dow; 1 female (4080). 



Panama; shore, on rocks, low tide; May-July, 1924; EUzabeth 

 Deichmann; 1 male, 1 female (60225). 



Ecuador: South side Point Santa Elena; September 17, 1926; 

 W. L. Schmitt; 1 female (60821). 



Paita, Peru; October 8, 1926; W. L. Schmitt; 1 female (60950). 



PILUMNUS HOLOSERICUS Rathbun 



Plate 207, Figures 8 and 9 



Piluranus holosericus Rathbun, Bull. Lab. Nat. Hist. State Univ. Iowa, vol. 4, 

 1898, p. 268, pi. 5, fig. 1 (type-locality, St. Thomas, Virgin Islands; Cat. 

 No. 19705, U.S.N.M.); BuU. U. S. Fish Comm. for 1900, vol. 20, part 2 

 (1901), p. 39. 



Diagnosis. — Covered with a smooth thick felt, concealing the 

 tubercles of the carapace in large part. Four lateral teeth. Half 

 or less than half of outer surface of major manus bare and smooth. 



Description. — Carapace suboval; dorsal surface entirely covered 

 with a dense pubescence forming a smooth felt-like surface but dis- 



