S. I. Smith on American CrusUicea. 125 



armed with three spimiles. The liaiid is slender, and the fingers are 

 long, flattened at the tips, and the angles clothed with long hairs. 



The ambulatory legs are stout. The merus is smooth and unarmed 

 in the lirst pair, but in the three last pairs, its posterior edge is 

 armed with slender spines, — live in the second pair, six or seven in 

 the third, and three short ones on the fourth or last. 



The abdomen is quite similar to that of G. princeps. 



Length of carapax, 25*2"""; breadth of carapax, 35 'S"""; ratio of 

 length to breadth, 1 : r41. Total length of propodus in larger cheli- 

 ped, 60-0'""\ Length of dactylus, 45 -6'"'"; breadth of dactylus, 

 11-8""". 



The only specimen of this species which I have seen is in the col- 

 lection of the Peabody Academy of Science, and was obtained at the 

 Gulf of Fonseca, West Coast of Central America, by J. A. McNiel. 



The larger hand in this specimen resembles very much the figure of 

 the hand of G. maracoani given by Edwards in the Annales des Sci- 

 ences naturelles, 3""^^ serie, tome xviii, 1852, pi. 3, fig. 1'', but the car- 

 apax and ambulatory legs seem to be very difterent from that species, 

 as neither Edwards nor Dana mention, in their descriptions of G. mar- 

 acoani^ the peciiliar sculpturing of the branchial regions, the tuber- 

 cles of the lateral margins or the spines of the ambulatory legs which 

 are so conspicuous characters in G. armatus. In these characters it 

 approaches the genus Acanthoplax, as described by Edwards. 



Gelasimus ornatus, sp. oov. 



Plate II, figure 9-9^ Plate III, figure 5-5<=. 



Female. The carapax is narrow and the greatest breadth is be- 

 tween the antero-lateral angles, it is convex longitudinally, but only 

 slightly laterally, and the dorsal surface is verrucose, some of the ver- 

 rucae, especially on the branchial regions, being large and depressed. 

 The regions are not swollen or protuberant, but the cervical and bran- 

 chio-cardiac suture is very distinctly indicated. The front is narrow 

 and spatulate, but only slightly expanded below" the bases of the ocu- 

 lar peduncles. The superior border of the orbit is slightly and regu- 

 larly arcuate, as seen from above, the margin is slightly raised and 

 minutely denticulate, and the lateral angle projects forw^ard and out- 

 ward as a slender and prominent tooth. The antero-lateral margin is 

 longitudinal for a short distance anteriorly, but the posterior jjortion 

 curves inward to the base of the posterior leg, and is ornamented 

 with eight to ten bead-like tubercles. The latero-inferior, branchial 

 regions are nearly vertical, and are divided by a granulated crest 



