S. T. Smith on American Crustacea. 147 



P. dentaia {Boscla dentata Edwards, Histoire naturelle des Crust., 

 tome ii, p. 15, pi. 18, fig. 14-16), from the West Indies. 



The only other described species is the jR sinutifrons [Boscia sinu- 

 tifrons A. Edwards, loc. cit., p. 205), the habitat of which was not 

 known. 



Pofamia latifrons Randall (Journal Academy Nat. Sci., Philadel- 

 phia, vol. viii, p. 120, 1839), supposed to have come from Surinam or 

 the West Indies, probably belongs here, but the description is too 

 indefinite to determine its aflSnities with any degree of certainty. 



Pseudothelphusa plana, sp. nov. 



Female. The carapax is very broad and its dorsal surface is flat in 

 the middle and posteriorly, but convex along the anterior border, and 

 is punctate, but the surface between the widely separated punctures 

 is glabrous. The gastric region is undivided, except by a short and 

 shallow median sulcus, which separates the slightly indicated anterior 

 lobes and extends down the front. The anterior portion of the cer- 

 vical suture, from the median lobes of the gastric region to the antero- 

 lateral margin, is well indicated by a straight, broad and deep sul- 

 cus. There is no sulcus between the gastric and hepatic regions. 

 The branchial regions are very prominent and undivided. The front 

 is deflexed and the narrow inferior margin is perpendicular, and has 

 a distinct submarginal groove. The orbits are well filled by the 

 stout ocular peduncles. The antero-lateral margin is evenly and very 

 strongly arcuate, and its edge is sharp and finely denticulated. The 

 postero-latei'al margin is concave in outline. 



The external maxillipeds, as well as the sternum, are punctate like 

 the carapax but the punctures are much larger. 



A single cheliped is quite small ; the merus scarcely reaches beyond 

 the carapax, is triangular, the anterior angle slightly dentate, and the 

 posterior angle rounded and granulated ; the upper side of the carpus 

 is punctate like the carapax, evenly rounded and armed with an angu- 

 lar tooth on the inner margin ; the basal portion of the propodus is 

 punctate, slender and evenly rounded ; and finally the fingers are long, 

 slender, cylindrical, nearly stiaight, and slightly toothed within. 



The ambulatory legs are naked, slender and rounded, and the 

 dactyli are nearly straight, cylindrical and sparsely spinulose. 



The color of alcoholic specimens is uniform dark olive brown above 

 and lighter beneath. 



Sex. Length of carapax. 



Female. IS-emm 



" 16-5 



