352 CRUSTACEA. 



The name of this genus is from the Greek X^T.?, gibbous, and 

 Grapsus. 



CYRTOGRAPSUS ANGULATUS. 



Carapax angulato-gibbosus, granulosus, nudus, margine antero-laterali 

 fere recto, k-dentato, margine postero-laterali leviter uni-dentato. Pedes 

 maris antici crassi, granulati, manu supra paulo truncatd, carpo intus 

 truncate. Pedes 8 postici fere nud.i, valde compressi, margine articuli 

 Stii superno subacuto, articulo 5to supra sulcato, tarso sulcato. 



Carapax angulato-gibbous, granulous, naked, antero-lateral margin 

 nearly straight, four-toothed, postero-lateral one-toothed. Anterior 

 feet of male stout, granulous, hand somewhat flattened above and 

 carpus flattened on inner side. Eight posterior feet nearly naked, 

 much compressed, upper margin of third joint subacute, fifth joint 

 sulcate above, tarsus sulcate. 



Plate 22, fig. 6 a, male, natural size; b, under view, ibid.; c, front 

 view of front ; d, sternum and abdomen, ibid. ; e, hand, natural size, 

 ibid. 



Rio Negro, Northern Patagonia. 



Length of carapax of a male, seventeen and three-fourths lines ; 

 breadth, twenty-one lines; length of front, six lines; breadth between 

 the post-orbital teeth, twelve and a half lines. In the male, the ridge 

 extending inward from the lateral tooth is rather sharp and the cara- 

 pax where it terminates is rounded prominent; the cardiac areolet 

 is well defined and separated by a deep suture from the preceding; 

 the intra-medial areolet is also well pronounced. 



C. angulatm, DANA, Proc. Acad. Nat. Sci. Philad., 1851, v. 250. 



