THE GEAPSOID CRABS OP AMEEICA. 261 



eept the hepatic, well marked. Antero-lateral borders armed with 

 three teeth behind the acute orbital angle, a raised line running in- 

 ward on the carapace from the last tooth. Carapace widest at the 

 last tooth. 



Front occupying half the distance between the postorbital angles, 

 rather prominent, slightly inclined, edge divided into two shallow 

 lobes. 



Orbits a good deal larger than the eyes; lower margin divided into 

 two parts which are discontinuous. Near the inner angle a triangu- 

 lar lobe arises from the orbital fossa and with an adjacent lobe of the 

 first movable joint of the antenna, half fills the inner hiatus of the 

 orbit; the second movable joint occupies the remainder of the hiatus, 

 permitting the flagellum to enter the orbit. 



Antennular cavities broadly triangular, the antennules folding 

 obliquely ; interantennular septum narrow. 



Epistome transverse, and shallow fore and aft. Buccal cavity 

 with sides parallel, anterior margin arched beyond the outer maxil- 

 lipeds, which have a moderate gape; merus and ischium of equal 

 length, merus wider than ischium and as wide as long, subcordate, 

 the thickened palp articulating at the middle of the anterior margin. 



Chelipeds equal, in the male heavy, from one and two-thirds to one 

 and three-fourths times as long as the carapace. Palms widening 

 distally, fingers narrow, hollowed underneath. 



Legs rather narrow, the second and third pairs much the longest. 

 Dactyli unarmed. 



Abdomen with seven segments in both sexes; and in the male 

 leaves the sternum exposed at its base. First segment with a promi- 

 nent transverse granulated ridge visible in a dorsal view. 



Comprises two species inhabiting South America. Species on both 

 sides of the continent : angulatus. 



KEY TO THE Sl'ECIES OF THE GENUS CTETOGRAI'SU.S. 



A*. Antero-lateral teeth prominent, projecting beyond the general outline of 

 the carapace angulatus, p. 261. 



A*. Antero-lateral teeth not prominent, not projecting beyonrl the general out- 

 line of the carapace ^altimanus, p. 262. 



CYRTOGRAPSUS ANGULATUS Dana. 



Plate 65 ; plate 159, figs. 7 and 8. 



Cyrtograpsus angulatus Dana, Proc. Acad. Nat. Sci. Philadelphia, vol. .5, 



1S51 (1852), p. 250 (type-locality, Rio Negro, Patagonia; holotype, Cat. 



No. 2346, U.S.N.M.) ; U. S. Expl. Exped., vol. 13, Crust, pt. 1, 1852, 



p. 352 ; atlas, 1S55, pi. 22, figs. 6 o-e. 

 Cyrtograpsus cirri pes Smith, Trans, Connecticut Acad. Arts and Sci., vol. 



2, 1S69, p. 11, pi. 1, fig. 3 (type-locality, Rio de Janeiro; male holotype. 



Cat. No. 6125, in Mus. Comp. Zool.). 



