S. J. Smith on American Cmstacea. 123 



cheliped entire, the hand much shorter and the fingers gaping for the 

 whole length, and wanting the stout tooth on the prehensile edge of 

 the propodus. 



G-elasimus maracoani Latreiiie. 



Maracoani, Marcgrave de Liebstadt, Ilistoire rerum naturalium Brasilise, figure. 



Ocypoda maracoani Latreiiie, Histoire des Crust, et Insectes, tome vi, p. 46, 1803. 



GonojHax maracoani Lamarck, Histoire naturelle des animaux sans vertebres, 2^ edit., 

 tome V, p. 465. 



Gelasimus maracoani Latreiiie, Nouveau Dictionnaire d'Histoire naturelle, 2^ edit , 

 tome xii, p. 517, 1817; Encyclopedie methodique, pi. 296, fig. 1; Edwards, His- 

 toire naturelle des Crust., tome ii, p. 51, 1837; Annales des Sciences naturelles, 

 3>ne serie, Zoologie, tome xviii, 1852, p. 144, pi. 3, fig. 1; Dana, United States Ex- 

 ploring Expedition, Crust, p. 318, 1852. 



Said to inhabit Cayenne and Brazil. 



Very likely two or more species are still confounded under the 

 name of maracoani. Neither Edwards nor Dana mention any spines 

 on the meral segments of the ambulatory legs, while in Latreille's 

 figure in the Encyclopedie methodique there are short spines repre- 

 sented on the posterior legs, 



Gelasimus armatus, sp. nov. 



Plate II, figure 5. Plate III, figure 4-4 ^i. 



Male. The carapax is only slightly convex and very little narrow- 

 ed posteriorly, and the dorsal surface is naked and deeply areolated. 

 The gastric and cardiac regions are smootli and shining, and the car- 

 diac is large and very prominent. The branchial regions are promi- 

 nent and their surfaces smooth but covered by very distinct, raised, 

 vein-like markings which branch off in an arborescent manner from a 

 conspicuous central trunk. The front is small, spatulate, contracted 

 between the bases of the ocular peduncles and expanded below. The 

 superior border of the orbit has a strongly raised margin, its edge is 

 slightly sinuous and the antero-lateral angle prominent, the one on the 

 side of the smaller hand being directed forward and the one on the 

 side of the larger hand being more prominent than the other and di- 

 rected strongly outward. The anterior part of the lateral margin is 

 longitudinal, so that the breadth of the carapax is scarcely more be- 

 tween the antero-lateral angles than a short distance posteriorly ; at 

 the posterior extremity of this longitudinal portion, there are two 

 small, but prominent, marginal tubercles, from which a graiudated 

 line extends to the bases of the posterior legs, where there is another 

 small rounded tubercle. The posterior margin is straight, smooth and 



