THE GEAPSOID CEABS OF AMERICA. 317 



late, lower edge projecting, quadrilobate. Middle pair of superior 

 lobes distinctly wider than outer pair. 



Upper margin of orbit convex; outer tooth acute, rather promi- 

 nent ; behind it on the lateral margin there is a blunt, obtuse-angled 

 rudiment of a tooth. 



The arm has a triangular projection from the distal half of its 

 inner margin. Palm very rough, Avith sharp granules which are 

 continued the length of the upper surface of the dactylus and the 

 lower surface of the pollex, Fingers remarkably modified in the 

 male ; the dactylus is depressed and flattened in its basal half, so that 

 it is one and one-half times as wide as high ; the dactylus is strongly 

 swollen below, so that its lower margin is very convex, independent 

 of the convexity of the palm. The fingers gape for their basal half 

 and are irregularly toothed on the distal half. 



Third leg a little less than twice as long as the carapace, its merus 

 twice as long as wide. 



Measurements. Male (22838), length of carapace 18.5, anterior 

 width of same 21.3, posterior width of same 20, width of front 

 13.3 mm. 



Range. Key West, Florida (M. C. Z.). Guiana to Rio de Janeiro, 

 Brazil (M. C. Z.). 



Material examined. 



Demerara, British Guiana; 1 male, 1 female (Brit. Mus.). 



Tajapouru, Brazil; Thayer Exped.; received from Mus. Comp. 

 Zool.; 1 male, 1 female (22838). 



Para, Brazil; Dr. T. B. Wilson; 2 males, 1 female, cotypes of S. 

 chiragra (Mus. Phila. Acad. Sci.). 



Genus METOPAULIAS Rathbun. 



Metopaulias RATHBITN, Proc. U. S. Nat. Mus., vol. 19, 1896, p. 144; type, 

 M. depressus Rathbun. 



Carapace perfectly flat. Supra-frontal lobes subtriangular or 

 obliquely truncated. 



Differs from Sesarma in having the carapace perfectly flat except 

 near the postero-lateral angles, where it is destitute of oblique ridges ; 

 the front deeply concave, both transversely and longitudinally, the 

 upper and lower margins deeply divided, the supra-frontal lobes 

 forming teeth which are subtriangular or obliquely truncated; the 

 granules of the side walls arranged singly, not in pairs. 



The antero-lateral margins are curved, unidentate, the extremities 

 of the fingers very narrow, with tips curved, legs long and slender. 



Known only from the type-species. 



