PART 1 GARTH : PACIFIC OXYRHYNCHA 217 



Genus SPHENOCARCINUS A. Milne Edwards 



Sphenocarcinus A. Milne Edwards, 1878, p. 135. Rathbun, 1925, p. 185. 

 Oxypleurodon Miers, 1886, p. 38; type: O. stimpsoni Miers, 1886, by 

 monotypy. 



Type: The Atlantic Sphenocarcinus corrosus A. Milne Edwards, 

 1875, by monotypy. 



Description: Carapace subpentagonal, broadened behind, tapering 

 gradually in front. Rostrum long and formed of two pointed horns, 

 joined one to another; no preorbital spine [this is not true of Spheno- 

 carcinus agassizi Rathbun]. Orbit incomplete below. Basal article of the 

 external antennae narrow, and the movable flagellum inserted under- 

 neath the rostrum, entirely hidden by it. Epistome narrow and long. 

 Third article of the external maxillipeds, or merus, dilated a little at its 

 anteroexternal angle, and slightly notched on the inner side for the in- 

 sertion of the palpus. 



Chelipeds slender and symmetrical ; the first pair of ambulatory legs 

 much longer than the others. (A. Milne Edwards, modified) 



Abdomen in both sexes with seven distinct segments. (Rathbun) 



Range: Pacific coast from off Cape Tepoca, Gulf of California, 

 Mexico, to Bahia Honda, Panama; Galapagos Islands. 14-90 fathoms. 

 Atlantic coast from off Cape Lookout, North Carolina, to Barbados. 

 To 100 fathoms. Indo-Pacific Ocean east to Hawaii. 



Contains two American species, one Pacific and one Atlantic. 



Sphenocarcinus agassizi Rathbun 

 Plate O, Fig. 1 ; Plate 25, Fig. 1 



Sphenocarcinus agassizi Rathbun, 1893b, p. 231; 1925, p. 188, pi. 63; 

 pi. 223, figs. 1, 2. Faxon, 1895, p. 7, pi. 1, figs. 3, 3a. Crane, 1937, 

 p. 58. Garth, 1946, p. 379, pi. 63, fig. 2. 



Type: Male holotype, U.S.N.M. No. 17343, length 35 mm, width 

 23 mm. 



Type locality: Off Cape Tepoca, Gulf of California, Mexico, 14 

 fathoms, Albatross station 3019. 



Localities subsequently reported, with collectors: Gulf of California, 

 Mexico: northwest of Guaymas, 71 fathoms, Albatross (Rathbun, 

 1893b) ; Arena and Gorda Banks, 40-70 fathoms, Zaca (Crane). Costa 

 Rica: Cocos Island, Bay of Panama, 66 fathoms, Albatross (Faxon). 

 Galapagos Islands, Ecuador : off Daphne Minor and Barrington Islands, 

 48-80 fathoms, Velero HI (Garth). 



