OXYSTOMATOUS AND ALLIED CRABS OF AMERICA I'Jl 



Costa Eica: Punta Arenas; P. Biolley; February 1907; 2 males, 

 2 females (39102); gift of J. Fid Tristan. 



Panama: Hassler Expedition; 2 females (6450, M. C. Z.). Pearl 

 Islands, Panama Bay; S. Garman; April 1875; 1 male (6451, M. C. Z.). 



Peru: Oyster beds of Matapalo (near Capon); R. E. Coker; Jan- 

 uary 23, 1908; 1 male, 1 female (40444); gift of Peruvian Government. 



Genus RANDALLIA Stimpson 



Randallia Stimpson, Proc. Boston Soc. Nat. Hist., vol. 6, p. 85, 1857 (type, 

 R. ornata Randall); Boston Journ. Nat. Hist., vol. 6, p. 471, 1857. — Miers, 

 Voyage of H. M. S. Challenger, Brachyura, vol. 17, p. 316, 1886. — Alcock, 

 Journ. Asiat. Soc. Bengal, vol. 65, p. 191, 1896. 



Carapace circular and convex, almost globular; front narrow, 

 usually broadly bidentate, and somewhat sunk behind the level of 

 the front edge of buccal cavern. Subhepatic or pterygostomian 

 regions convex and puffed out. A broad vertical interval between 

 the orbits and the edge of buccal cavern. Surface of carapace usually 

 covered with vesicular or pustulous granules, but these are some- 

 times visible only with a lens. Regions usually, but not always, 

 distinctly demarcated by grooves. Posterior margin generally, but 

 not always, armed with spines or petaloid lobules or tubercles. Upper 

 edge of orbits deeply emarginate, a wide gap at inner canthus, and 

 three very distinct sutures in the upper-outer wall. The antennules 

 fold obliquely; antennae loosely lodged in the inner canthus of the 

 orbits. Exognath not dilated, outer margin almost straight; merus of 

 endognath about two-thirds the length of ischium measured on inner 

 edge . Chehpeds either massive or moderately stout, of moderate length ; 

 fingers stout, less than twice as long, or nearly as long as hand, which is 

 usually much less than half the length of carapace. (After Alcock.) 



California to Peru; Pacific Islands; Indian Ocean; CuraQao; [south] 

 Trinidad Island, Brazil; shallow water to 350 fathoms. 



KEY TO THE AMERICAN SPECIES OP THE GENUS RANDALLIA 



A'. Five protuberances on posterior part of carapace, including one 

 on intestinal region. 

 B*. Three well-separated tubercles on lateral margin of cara- 

 pace, aside from the spine on posterolateral margin. 

 C*. Chelipeds of male one and one-half times as long as cara- 

 pace. Carapace granulate, distinctly longer than 



broad ornata (p. 172) 



C^. Chelipeds of male nearly three times as long as carapace. 



Carapace smooth, about as broad as long laevis (p. 177) 



B'. A row of several tubercles or large granules on anterolateral 

 margin. 

 C*. Carapace with large, globular tubercles. Edge of efferent 



branchial channel trilobed bulligera (p. 17G) 



C^. Carapace with large granules on a background of fine ones. 

 Edge of efferent branchial channel entire. Front pro- 

 duced americana (p. 182) 



80232—37 12 



