42 CALIFORNIA ACADEMY OF SCIENCES. 



spines or teeth on the outer margin of the basal anteuual joint behind the 

 one at the anterior angle. Preorbital spine acute. Pterygostomiau 

 regions with several rounded teeth. Chelipeds of the male large, the 

 merus subcyliudrical (somewhat flattened below), and strongly pustulate, 

 especially at the angles; the carpus is pustulate and may have several 

 ridges on the outer side; hand long, narrow, compressed, the palm below 

 the wide cariua often inflated; fingers deflexed and, in old males, gaping 

 at the base, in which case there is generally a large tooth near the base of 

 the dactyl. Legs subcylindrical, more or less pubescent, the propodi 

 sulcate on either side; dactyls considerably shorter than the propodi and 

 furnished with sharp, corneous tips. The third, fourth, fifth and sixth 

 abdominal segments in the male are of nearly equal length; the seventh is 

 longer than broad and rounded at the tip; the abdomen tapers most at the 

 third and fourth segments, the fifth and sixth being of subequal width. 



Length of carapace: male 35 mm. 



Width of carapace 26 mm . 



Length of cheliped 55 mm. 



Length of first ambulatory leg 40 mm. 



Length of carapace: female 25 mm. 



Width of carapace 16 mm. 



Length of cheliped 28 mm. 



Alaska, British Columbia, Oregon, Farallon Islands! 

 southern California! Santa Catalina Island! San Diego! 



The individuals of this species vary considerably with 

 age. In the old males the tubercles on the carapace are 

 rougher and more prominent, the posterior tubercle on 

 the branchial region projecting over the sides of the 

 carapace ; the horns of the rostrum become much 

 widened at the base ; and the chelipeds are much 

 larger. In the females the tubercles on the carapace 

 are smoother, those on the median region being small 

 or obsolescent. 



Family PERICERID.E. 



Eyes retractile within the small, circular, and well defined orbits which 

 are never incomplete as in the Maiidae. Basal antennal joint well devel- 

 oped, and constituting the greater part of the inferior wall of the orbit. 



