THE GBAPSOID CRABS OF AMERICA. 55 



gers long and slender, third pair of legs longest, dactylus of last 

 pair recurved. Abdomen of male much narrower at base than the 

 sternum ; third to fifth segments fused. 



Restricted to America and the Philippine Islands. Analagous 

 species on opposite sides of the continent: typicus (Atlantic) ; Jatipes 

 (Pacific). 



KEY TO THE AMERICAN SPECIES OF THE GENDS CHASMOCARCINOS. 



A\ Orbits transverse in dorsal view. Carapace strongly narrowed anteriorly. 



typicus, p. 55. 

 A*. Orbits oblique in dorsal view. 

 B\ Orbits directed obliquely forward and outward. Merns joints of legs 



broad httipes,\).57. 



B*. Orbits directed obliquely backward and outward. Merus joints of legs 

 narrow. 



C\ Carapace narrow, not mucli broader than long obliqmis. p. 58. 



C. Carapace broad, much broader than long cylindricus, p. 59. 



FlO. 23. CHASMOCAKCINDS TTPICUS, MALE HOr.OTYrE. a, DOUSAL VIEW, X 2 ; b, AB- 

 DOMEN AND STEItXUM, FLATTENED, X 2. 



CHASMOCARCINUS TYPICUS Rathbun. 



Chasmocarcinns typicus Rathbttn, Bull. Lab. Nat. Hist. State Univ. Iowa, 



vol. 4, 1S9S, p. 285, pi. 7, figs. 3-5 (type-locality, north of Trinidad, 



31 to 34 fathoms, stations 2121 and 2122, Albatross; male holotype, 



Cat. No. 6901, U.S.N.M.). 



Diagnosis. — Orbits transverse. An antero-lateral marginal line. 



Sternum and abdomen granulate. 



Description. — Carapace a little more than three-fourths as long as 

 broad. Upper surface convex, rounding gradually downward into 

 the nearly perpendicular lateral surfaces. Anterior third strongly 

 deflexed. Lateral outline as seen from above convex and slightly 

 emarginate at its middle where a sulcus arises which extends 



