S. I. Smith on American Crustacea. 157 



broad depression and is somewhat separated from the rather broad 

 mesogastric lobe, which extends forward, in the median sulcus between 

 the protogastric lobes, nearly to the front. This median sulcns is 

 broad and very deep, with precipitous sides and cuts through the 

 whole height of the frontal crest. The branchial regions are trav- 

 ersed by sharp transverse plications. The fi'ont is perpendicular and 

 low, and the inferior margin is broken by a broad excavation in the 

 middle, where it scarcely projects beyond the epistome ; above the 

 antennulffi the edge projects, but toward the orbit slopes otf again. 

 The antero-lateral margin is armed with two stout teeth (including 

 the angle of the orbit) and with the trace of a third. The first tooth 

 is acute, dii'ected forward and situated below the level of the rest of 

 the margin, the second is prominent, acute, and projects forward par- 

 tially over the deep, rounded incision which separates it from the first 

 tooth, and the third is only indicated by a slight emargination. 



The chelipeds are equal and rather small ; the merus is rough ex- 

 ternally, the angles are sharp and the anterior ones serrate ; the cai*- 

 pus is very granulous externally ; and the hand is slightly compressed, 

 smooth externally, and the superior margin armed with a sharp crest. 



The ambulatoiy legs are stout and much compressed, the meral seg- 

 ments are very broad, the breadth being equal to half the length, and 

 rough with short transA^erse plications, the propodi and dactyli ai'e 

 hairy along the edges, and the dactyli are stout, curved and acumi- 

 nate. 



Length of carapax, 25-0™'"; greatest breadth of carapax, 3rO'"'^; 

 ratio of length to breadth, 1:1*24. Breadth of carapax between 

 antero-lateral angles, 29-5""". Breadth of front, 16-4'"'" ; height of 

 front, 3 •4""". 



The single specimen described was obtained at Corinto, west coast 

 of Nicaragua, by J. A. McNeil, and is in the collection of the Pea- 

 body Academy of Science. 



Sesarma cinerea Say. 



Grapsus cinereus Bosc, Histoire naturelle des Crust., tome i, p. 204, pi. 5, fig. 1, 1802 ; 

 Latreille, Histoire naturelle des Crust, et Insects, tome, vi, p. 72, 1803. 



Grapsus {Sesarma) cinereus Say, Journal Academy Nat. Sci., Philadelphia, vol. i, p. 

 442, 1818 {non Grapsus cinereus Say, loc. cit, p. 99, 1817). 



Sesarma cinerea Edwards, Histoire naturelle des Crust, tomeii, p. 75, 1837; Annales 

 des Sciences naturelle, 3™^ serie, Zoologie, tome xx, 1853, p. 182 ; Gibbes, Proceed- 

 ings American Association, 3d meeting, p. 180, 1850; Stimpson, Annals Lyceum 

 Nat. Hist, New York, vol. vii, p. 65, 1859. 



