18 CALIFORNIA ACADEMY OF SCIENCES. 



bearing a few setae at the subacute tip. Basal antennal joint with a longi- 

 tudinal ridge on its posterior half or two-thirds with a groove on either 

 side. Ischium of maxillipeds with a shallow, longitudinal groove; merus 

 narrower than ischium, the internal angle produced, and the surface 

 stronglj^ concave from side to side. Chelipeds in the male robust; merus 

 incurved and having an outer spiny ridge; carpus with a posterior spine 

 on the upper side; hand oblong, incurved, palm inflated, fingers gaping 

 at the base and meeting along the distal half, or two-thirds of their 

 length; there are generally several small, spiny projections on the surface 

 of the hand, which are more conspicuous along the edges, especially the 

 lower. In the female the chelipeds are smaller and more slender, the 

 hands subcylindrical, and the fingers nearly straight. Legs very long and 

 slender, and furnished with tufts of long setse, those on the upper side 

 being curved; dactyls slender, falciform, those of the first pair about one- 

 third the length of the propodi, and a little more slender but not more 

 curved than the others; in the two posterior pairs the dactyls are about 

 one-half the length of the propodi. Abdomen of the male six-jointed from 

 the fusion of the last two joints; first two joints visible from above; the first 

 joint is much longer but not so wide as the second; the second, third, and 

 fourth joints decrease successively in width but are of nearly equal length; 

 the fifth is longer than the preceding and the sixth is oblong, rounded at the 

 tip, and much longer than any of the others; the sides of the abdomen 

 behind the second joint are concave and at the middle of each joint there 

 is a conical protuberance, the last joint bearing traces of two. In the 

 female the abdomen is large and rounded and composed of five joints 

 from the fusion of the last three; it fits closely over the thin, laminate rim 

 which encloses the greater portion of the sternum. As the sternum and 

 the ventral surface of the abdomen, are both hollowed out, there is thus 

 formed a quite capacious chamber for holding the ova. 



Length of male 26 mm.; breadth 17 mm.; length of first ambulatory 

 legs 60 mm. 



San Diego (Lockington); Santa Catalina Island, 

 dredged August, 1893! Off Cape :St. Lucas and Gulf 

 of California (Miss Rathbun); Magdalena Bay, Lower 

 California! 1 have seen Lockington's specimens from 

 the latter locality, and Miss Rathbun's types of tenuipes 

 from Catalina. 



Subfamily INACHIN^. 



Eyes slender and retractile. Basal antennal joint usually slender 

 throughout, not narrowing distally. Preocular spine often wanting; 

 postocular distinct. Kostrum often bifid or two-spined. 



