126 S. I. Smith on American Crustacea. 



which starts a little way from tlie antcro-lateral angle and extends 

 obliquely backward to the bases of the penultimate legs. The poste- 

 rior margin is ornamented with a line of low tubercles. The inferior 

 margin of the orbit is armed with about fifteen compressed and trun- 

 cate teeth. The jugal regions are rough and sparsely clothed with 

 short hairs. 



The ocular peduncles are equal in length, slender, slightly enlarged 

 at the cornea and very little shorter than the broad and very open 

 orbits. 



The chelipeds are like the smaller cheliped of G. armatus, except 

 that the merus has but one spine and that the ischium has a slight 

 tooth on the lower side next the articulation with the merus. 



The ambulatory legs are quite similar to those of G. armatus, but 

 all of them have a tooth or spine on the lower side of the ischium, 

 and the merus is armed in the first i)air with one or two spines, in the 

 second with three, in the third with five, and in the last with two or 

 three. 



The abdomen is broadly elliptical, and the basal segment is orna- 

 mented with a line of small tubercles. 



Length of carapax, 26-6™'" ; breadth of carapax, 36-0'""" ; ratio of 

 length to breadth, 1 : 1'35. 



The single specimen above described is in the collection of the Pea- 

 body Academy of Science, and was brought home, with the G. arma- 

 tus and several of the foregoing species, by J. A. McNiel, but unfor- 

 tunately has no label to indicate the exact locality from which it came. 

 It is however undoubtedly from some part of the west coast of Cen- 

 tral America. 



This species is allied to the Acanthoplax insignis Edwards, but is 

 at once distinguished from it by the verrucose dorsal surface of the 

 carapax. It has also considerable affinity with G. armatus, and it is 

 possible that it may be the female of that species, but this seems very 

 improbable, when the great diflerences in the ornamentation of the 

 carapax and in the armature of the chelipeds and ambulatory legs are 

 considered. 

 G-elasimus insignis. 



Acanthoplax insignis Edwards, Annales des Sciences naturelles, 3™e serie, Zoologie, 

 tome xviii, 1 852, p. 151, pi. 4, fig. 23 ; Archives du Museum d'Histoire naturelle, 

 Paris, tome vii, p. 162, pi. 11, fig. 1, 1854. 



Edwards states that this species was known to him only from a sin- 

 gle, female specimen brought from Chili by M. Gay, but the figures 

 which he has given in the Annales des Sciences and in the Archives 



