158 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.21 



usually more produced laterally; the two rows therefore joining in a 

 curve, not at an angle. Another row of spines forming the lateral supra- 

 marginal border of the branchial region, and continuing on the ptery- 

 gostomian region; from this row a short branch running up on the 

 branchial region. An irregular row of small spines crossing the gastric 

 region. Orbits, outer margin of the postorbital teeth and the inferolateral 

 and posterior margins of the carapace armed with spinules. Rostral 

 horns more upturned than in Chionoecetes opilio and a little longer and 

 narrower, leaving a wider interspace. 



Posterior margin of epistome strongly deflexed in the center and 

 arched at the sides. The external maxillipeds when in place not fitting 

 closely into the buccal cavity, as in Chionoecetes opilio ; merus with 

 spinous margins. 



Ambulatory legs armed with longer and stouter spines than in 

 Chionoecetes opilio. In adults more than in young the legs longer in 

 C. tanneri, especially the meropodites, which are much narrower, and in 

 the male do not widen at the proximal end as in C. opilio. Legs of 

 female shorter than of male, as is the case in C. opilio. 



Second segment of male abdomen bent downward at lateral ex- 

 tremities in almost a right angle. On the sternum in front of the abdomen 

 a transverse ridge of sharp tubercles. (Rathbun, 1925, modified) 



In redefining the species subsequent to the description of Chionoecetes 

 angulatus, Rathbun (1925, p. 243) was careful to state that the outer 

 spine of the oblique branchial row is as large as the outer spine of the 

 transverse row, is directly in front of it, and is usually more produced 

 laterally ; the two rows therefore join in a curve and not at an angle, as in 

 C. angulatus. 



Material examined: Off Point Sur, California, 475 fathoms, April 

 27, 1911, Albatross station 5698, 1 male (photographed), 1 female 

 (U.S.N.M. No. 47096). 



Measurements: Male specimen: length 31.0 mm, width excluding 

 lateral spines 29.0 mm, rostrum 3.6 mm, width 4.4 mm, cheliped 31.2 

 mm, chela 14.2 mm, dactyl 9.3 mm, ambulatory legs 71, 73, 69, and 

 40 mm, respectively. Female: length 31.0 mm, width 29.1 mm. 



Color in life: Unknown. 



Habitat: Green mud, fine gray sand; rock occasionally present. 

 (Rathbun, 1925) 



Depth: 29-1,062 fathoms. (Rathbun, 1925) 



Breeding: Ovigerous females were obtained by the Albatross off 

 Monterey Bay, off Santa Cruz Island, and off Santa Catalina Island in 

 April, and off San Clemente Island in April and in May. 



