330 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 21 



tubercles on dactylus and between these one on pollex, distal half of 

 fingers denticulate. 



Ambulatory legs cylindrical, the first nearly as long as the cheliped, 

 the remainder diminishing regularly in length ; meri granulate but not 

 tuberculate ; carpi longitudinally sulcate ; dactyli stout, incurving. 



Male abdomen with seven free segments, a stout tubercle at middle 

 of segment one, a lesser tubercle on succeeding segments, widest opposite 

 segments two and three, sides of segments four to six subparallel, sides 

 converging from middle of segment six, tip triangular. 



Male first pleopod coarse, tip acute, bent sharply, grooved, a blunt 

 but well developed keel on opposite side, tip and keel minutely spinulous. 

 (See Plate T, fig. 6) 



Female similar to male as regards general shape and tuberculation of 

 carapace. Rostrum shorter at base, horns equally or more strongly diverg- 

 ent. Lateral marginal ridge less prominent than in male; hooked hairs 

 more abundant and conspicuous. Chelipeds weak, especially chelae, which 

 are almost filiform. Dactyli long and slender, crenulate, gaping narrowly, 

 the three teeth of adult male lacking. Abdomen orbicular, a tubercle on 

 narrow first segment. 



A young male of 40 mm agrees with the female in lacking the digital 

 teeth of the cheliped. 



Material examined: 4 specimens from 2 lots, all U. S. National 

 Museum material: Paita, Peru, October 8, 1926, W. L. Schmitt, col- 

 lector, Walter Rathbone Bacon Fellowship, donor, 1 male, 1 female 

 (U.S.N.M. No. 76573) ; Paita, Peru, October, 1926, W. L. Schmitt, 

 collector, Walter Rathbone Bacon Fellowship, donor, 1 male (U.S.N.M. 

 No. 70999), 1 male neotype (U.S.N.M. No. 100916). 



Measurements: For critical comparison measurements of a male and 

 female of approximately equal size are given in tabular form : 



