570 CALIFORNIA ACADEMY OF SCIENCES, 



wards to the broad, slighth' concave posterior margin. 

 Front short, deflexed, and not projecting beyond the gen- 

 eral contour of the carapax; it is furnished with a short 

 median groove, but the transverse groove behind the an- 

 terior margin, which is so conspicuous in P. loiigipes, is 

 sHghtly or not at all marked. Antero- lateral margins 

 marked by a ridge along their distal portion which inter- 

 sects the postero-lateral margin at somewhere near a right 

 angle. Maxillipeds pubescent; the postero-internal angle 

 of the meros is curved inward, and the distal portion of 

 the outer margin is convex; penultimate joint of the palp 

 oblong-ovate ; the last joint is spatulate and is joined near 

 the base of, and extends considerably beyond, the pre- 

 ceding joint; exopod rather broad, and bearing a rounded 

 projection near the middle of the outer side, beyond which 

 the margin is concave. Chelipeds rather small, shorter 

 than the second ambulatorv leo-s, meros much larjjer than 

 the carpus; hand oblong, compressed, longer than the 

 combined lengths of all the preceding joints; fingers a 

 little over one-half the length of the palm; the tips of the 

 lingers are hooked and their inner margins meet when 

 they are closed. The first pair of ambulator}^ legs is 

 slender and furnished with rather slender tarsi which are 

 about equal in length to the propodi. The second pair is 

 much longer and stouter than the first and have relatively 

 somewhat stouter tarsi which are a little shorter than the 

 propodal joints. The third pair of ambulator}^ legs is 

 stouter and a little longer than the second and .are furnished 

 with shorter and stouter tarsi which are conspicuously 

 shorter than the preceding joint. The fourth pair is similar 

 in character to the third but rarelv extends beyond the dis- 

 tal end of the meros of the preceding pair. Abdomen of 

 female transverseh' elliptical, the first joint very short, 

 the second about one -half as lono- as the third. Abdo- 



