THE SPIDER CRABS OF AMERICA 



187 



though stout, recurved and prehensile, are^ not toothed along the 

 posterior edge. Abdomen in both sexes with seven distinct segments. 

 East and west coast of middle America. Indo-Pacific region 

 from the western Indian Ocean to the Hawaiian Islands. Depth, 14 

 to 300 fathoms. 



KEY TO THE AMERICAN SPECIE3 OF THE GENUS SPHENOCARCINVS 



A'. Dorsal surface deeply channeled. Antero-lateral margin entire. 



corrosus, p. 187. 



A^ Dorsal surface uneven but not deeply channeled. Antero-lateral margin 



coarsely dentate agassizi, p. 188. 



Analogous species on opposite sides of the continent: corrosus 

 (Atlantic) ; agassizi (Pacific) . 



SPHENOCARCINUS CORROSUS A. Milne Edwards 



Plate 62; plate 223, figs. 3-5 



Sphenocarcinus corrosus A. Milne Edwards, Crust. Reg. Mex., 1875, pi. 

 17, figs. 5-5c; 1878, p. 136 (type-locality, off Barbados, 100 fathoms; 

 holotype in Mus. Comp. Zool.). — Rathbun, Proc. U. S. Nat. Mus., vol. 

 17, 1894, p. 66.— Faxon, Mem. Mus. Comp. Zool., vol. 18, 1895, p. 8.— 

 Hay, Bull. Bur. Fisheries, vol. 35, 1918, p. 460, pi. 39, fig. 1.— A. Milne 

 Edwards and Bouvier, Mem. Mus. Comp. Zool., vol. 47, 1923, p. 378 1 

 text-fig. 18. 



Diagnosis. — Carapace deeply channeled between large, eroded 

 tubercles. Antero-lateral margin entire. Rostrum longer than 

 postrostral portion of carapace. 

 Description. — Antero-lateral margin of carapace concave, postero- 

 lateral margin convex. Dorsal surface deeply 

 channeled; the elevations thus formed are 

 coarsely punctate or eroded, and form a regular 

 pattern; one gastric elevation is longitudinal- 

 ly placed and widens behind; with a small, 

 circular lobe on each side it resembles a clover 

 leaf; cardiac lobe transversely elongate with a 

 deep notch on each side of its posterior mar- 

 gin; an intestinal lobe follows the posterior 

 margin; a lateral lobe (paired) extends from 

 behind the lateral angle forward nearly to the 

 eye; a small postocular and a larger supraocu- 

 lar elevation. Rostrum normally longer than 

 carapace, composed in greater part of two 

 Fic. 73.-spHENocARc.NU3 COR- Cylindrical liorns which are contiguous to near 

 Rosus, FEMALE (15183), MAX- tlic tlps, or occasloually divergent for a con- 

 iLLiPED, X 16 siderable distance. Two short rostrums have, 



in one case, horns wholly divergent; in the other, no sign of bifurca- 

 tion, but a simple, acute tip. 



