368 BULLETIN 97, UNITED STATES NATIONAL MUSEUM. 



Ocypode albicans LATBEILLE, Hist. Nat. Crust., vol. G, an XI [1802-1803], 



p. 48. 

 Ocyvodc arenarins SAY, Journ. Acad. Nat. Sci. Philadelphia, vol. 1, 1817, 



p. G9 (type-locality, "Inhabits sandy beaches of the sea, in holes of 



considerable depth"; a specimen (perhaps cotype) was presented by 



Say to the Brit. Mus.). 

 Monolcjns incrmis SAY, Journ. Acad. Nat. Sci. Philadelphia, vol. 1, 1817, p. 



157 (type-locality, eastern shore of Maryland; type not extant); 



larval stage. 

 Ocypoda arcnuria MILNE EDWARDS, Hist. Nat. Crust., vol. 2, 1837, p. 44, 



pi. 10, figs. 13 and 14. MIEKS, Ann. Mag. Nat. Hist, ser. 5, vol. 10, 



1882, p. 384, pi. 17, figs. 7-7&. 

 Ocypode albicans RATHBUN, Proc. Washington Acad. Sci., vol. 2, 1900, 



p. 134. 



Diagnosis. Outer angle of orbit less advanced than the front 

 Eyes without style. Fingers pointed. 



Description. Greatest breadth, which is a fifth more than greatest 

 length, is at the anterior third of the carapace. Lateral borders an- 

 teriorly convex, but posteriorly slightly concave or straight. Front 

 and side margins beaded or serrulate. The H -form depression in the 

 center of the carapace, the anterior half of the cervical suture, and 

 the lobe at the inner angle of the branchial region are well marked. 

 Granulation of surface coarser on the sides and along the front 

 than elsewhere. 



Upper border of orbit transverse and very sinuous, the outer angle 

 acute, less advanced than the front; lower border notched at the 

 middle, and with a triangular sinus below the outer angle. The 

 eyes do not reach the outer angle. 



Chelipeds rough, merus and carpus moderately so, merus serrulate 

 above, toothed on lower margins; carpus with a sharp spine at 

 inner angle. Chelae coarsely scabro-tuberculate ; margins of palm 

 and fingers dentate; fingers pointed. Stridulating ridge of larger 

 palm less than half greatest width of palm and composed of 14 or 15 

 small tubercles. It plays against a smooth ridge along the distal 

 half of the upper margin of the lower surface of the ischium. 



The ambulatory legs are almost smooth, fringed with long yellow 

 hair; the second pair the longest, about two and two-thirds times 

 length of carapace; the third pair a little shorter; the last pair much 

 the shortest, reaching only to distal fourth of propodus of third pair. 

 Merus of first three pairs broadened; propodus of same pairs with 

 longitudinal brushes of hair on anterior surface. Dactyli of all 

 fluted, depressions hairy. 



Color. Pepper-and-salt, pale yellow, straw-color or yellowish- 

 white, imitating the color of the beaches (Verrill). Sometimes light 

 amber and often iridescent. 



Measurements. Length of carapace of male (113C7) 44, width of 

 same 50.2 mm. 



