112 SMITHSONIAN MISCEIvLANEOUS COLLECTIONS 



C. frontalis Milne Edwards (Mel. Carcin., p. 170) must be closely 

 allied to, if not identical with, this species, but appears to have two> 

 more complete rows of spines on the upper side of the penult joint 

 of the walking-feet. 



This species was found in the paddy-fields at Loo Choo. The 

 fields lie mostly under water, and the animal probably burrows in 

 their banks. 



BOSCIAD^ ^ 



Genus POTAMOCARCINUS Milne Edwards 



177. POTAMOCARCINUS ARMATUS ^ Milne Edwards 



Potamocarcinus armatus Milne Edwards, Arch, du Museum d'Hist. Nat.,, 

 vn, p. 174, pi. xni, fig. 3. 



We have but one specimen of this species, a small male, half an 

 inch in length. It differs somewhat from the large female described 

 by Milne Edwards, in that the carapax is punctated and, toward the 

 lateral margins, somewhat granulated. The second and third antero- 

 lateral teeth are bifid. Dactyli scarcely quadrangular, almost 

 rounded; also smaller and less spinulose. 



It was found at Omotepec Island, in Lake Nicaragua, by Mr.. 

 Charles Wright, botanist of the expedition. 



THELPHUSID^ 



Genus GEOTHELPHUSA Stimpson 



This name is proposed for that group of Thelphiiscc which is char- 

 acterized by the obsolescence of the postfrontal crest and the epi- 

 branchial teeth of the antero-lateral margins. In the shape of the 

 carapax they have some resemblance to the Gecarcinidse, and they 

 approximate to that family also in their habits, frequenting the dry 

 land much more constantly than the typical Thelphtiscc. 



178. GEOTHELPHUSA DEHAANI - Stimpson 



Plate XVII, Fig. 2 



Thelphusa berardi De Haan, Fauna Japonica, Crust., p. 52, pi. v-i, fig. 2- 



(non Auct). 

 Thelphusa dehaanii White, Cat. Brit. Mus., 1847, p. 30. Milne Edwards,. 



Mel. Carcin., p. 178. 



'^Potamocarcinus nicaraguensis Ratlibun. 



' Potamon (Potamonautes) dehaanii (White). 



