160 S. I. Smith on American Crustacea. 



and the anterior portion of tlie meso-gastric lobe extends forward, 

 almost to the line of the front, as a very narrow ridge in the deep sul- 

 cns between the protogastric lobes. The median and posterior regions 

 are punctate with irregular, coarse punctations, and the branchial re- 

 gions are sliglitly plicate transversely. The front is nearly perpen- 

 dicular, but low and very concave, tlie superior crest projects almost 

 as far forward as the inferior margin, and is divided into four equal 

 lobules by a deep median groove and slight lateral ones, and the infe- 

 rior margin is strongly reflexed, its edge sinuous, as seen from above, 

 wnth a broad and shallow sinus in the middle, and a very slight one 

 each side. The antero-lateral tooth is nearly right-angular, and pro- 

 jects but slightly forward. The lateral margin is straight and entire. 



The chelipeds are equal and very small, the merus and carpus are 

 sharply granulous externally, the hand is about half as long as the 

 breadth of the front, slender, the inferior edge evenly rounded, and 

 the superior edge more angular and sparsely granulous, but not crest- 

 ed, and the fingers are slender, nearly cylindrical, and very slightly 

 toothed within. 



The ambulatory legs are very long and slender, even longer than in 

 /S. angustipes, and the meri and propodi are rough above. 



Length of carapax, from its posterior margin to superior lobes of 

 the front, 14-1""" ; breadth of carapax, 13-8'"™ ; ratio, 1 : 0-98. Breadth 

 of carapax between antero-lateral angles, 13*6™"\ Breadth of front, 

 '7-2; height of front, 1"8. Length of ambulatory legs, first, 22*0; 

 second, 28*4; third, 32'0; fourth, 25-0. Length of jjropodus in first 

 pair of ambulatory legs, 5 '6 ; second pair, 8*0 ; third pair, 9-0 ; fourth 

 pair, 6*6. 



I have seen only one specimen, a female, collected at the Pearl Isl- 

 ands, Bay of Panama, by F. H. Bradley. 



It is readily distinguished from all the other described American 

 species of the genus by the narrowness of the carapax, the low, per- 

 pendicular and excavated front, and the great length of the ambula- 

 tory legs. 



GONOPLACID^. 

 Prionoplax Edwards. 



Prionoplax ciliatus, sp. nov. 



A species similar to P. spinicarpus Edwards, Archives du Museum 

 d'Histoire naturelle, Paris, tome vii, p. 167, pi. 11, fig. 3. 



