238 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 21 



domed cardiac region; ridges, extending medially from each branchial 

 lobe and turning abruptly downward to parallel the sinuous posterior 

 margin, having a pinched appearance. Gastric elevation separated from 

 each protogastric by the shallowest of grooves; each hair-tipped proto- 

 gastric tubercle in turn separated by a faint median depression. 



Basal antennal article tapering rapidly from base to summit, longi- 

 tudinal ridge culminating in a tooth. First two movable articles slen- 

 der, cylindrical, tip only of flagellum extending beyond rostrum. 

 Ischium of external maxilliped with a linear groove, sides parallel, inner 

 margin hirsute ; merus subquadrate, sharply notched at anterointernal 

 angle to receive palpus, a strong tubercle on its midproximal surface. 



Chelipeds of adult male massive, grossly disproportionate in size to 

 walking legs and to carapace, except as suggested by anterolateral pro- 

 jections. Merus greatly elongated and swollen medially, tapering prox- 

 imally and distally, a tooth at base of outer margin and a number of 

 rough tubercles on inner margin. Carpus suborbicular. Manus equaling 

 or exceeding merus in length, smooth except for scattered granules, 

 slightly swollen medially, broadening distally to high point over palm. 

 Dactylus stout, curving strongly downward, meeting pollex along broad 

 outer, opaque ridge, inner margin with a comb of shaggy hairs. Pollex 

 deflexed, recurving, weakly toothed, and similarly hairy. Ambulatory 

 legs slender, only the dactylus of the first overreaching the merus of the 

 cheliped, decreasing regularly in length from first to last, meri only 

 roughened to any extent, those of the first leg with two or three tubercles 

 beneath, propodi laterally compressed, dactyli moderately recurved, pro- 

 vided with two rows of spinules and a stout nail. 



Abdomen of male with segments 3-5 fused, widest at base of sixth 

 segment, tip rounded. Sternal somites distinct and well separated. Tip of 

 male first pleopod acute, a rounded flange or heel on opposite side of 

 orifice. 



The female allotype differs from the holotype in having a shorter 

 rostrum, a less produced hepatic lobe, more broadly rounded and carry- 

 ing an accessory lobe on its anterior margin, the chelipeds less strongly 

 developed but more tuberculate, the meri of the walking legs similarly 

 roughened. Female abdomen orbicular and with segments 4-6 fused. 



Material examined: Seven specimens from four localities, all in the 

 Gulf of California. (See Table 47) From Punta Cholla, Sonora, to 

 Maria Magdalena Island, Nyarit, Mexico. 



Depth: Shore to 13 fathoms. 



