188 CALIFORNIA ACADEMY OF SCIENCES. 



iiarrow, deep, longitudinal sulcus extends backwards on the upper edge 

 in the larger hand almost to the posterior margin, but about two-thirds 

 as far in the smaller one; fingers longitudinal, subequal (the dactyl slightly 

 the longer), and working nearly vertically; pollex rather slender, tapering, 

 the tip curved upwards and the inner margin armed near the base with 

 two or three small teeth; dactyl, with one or two very small teeth near the 

 base of the straight inner margin, the tip curved and crossing that of the 

 pollex when closed; smaller hand more slender than the larger one, the 

 fingers somewhat narrower, otherwise very similar. Carpus of the second 

 pair of legs five-jointed, the first joint about as long as the four following 

 ones combined, second, third and fourth joints subequal, the fifth a little 

 longer; hand narrow, the fingers longer than the palm. Posterior pairs 

 of legs slender; merus and carpus devoid of spines; dactyls with very 

 slender tips. Sixth abdominal segment with a postero-lateral spine. Tel- 

 son tapering, rounded above where it is furnished with two pairs of spin- 

 nles, the tip rounded. 



Length of body, 18 mm.; of carapace, 6.5 mm.; of larger hand, 7 mm.; 

 of smaller hand, 5 mm. 



Monterey (Lockington)! Santa Barbara! 



Mr. Kingsley has united A. equidactylus Lock, with 

 A. heterochelis Say, 1 probably on Lockington's authority, 

 for he says: "Mr. Lockington informs me that his A. 

 equidactylus, from Monterey, Cal., presents no appreci- 

 able differences from specimens of A. heterochelis, from 

 Florida, that I sent him." There is evidently a mis- 

 take here, for heterochelis and equidactylus are so differ- 

 ent that it is scarcely credible that they should be 

 regarded as members of the same species by anyone 

 who had carefully compared them. Lockington's spe- 

 cies was described from a single, imperfect, dried speci- 

 men which had lost one of the anterior chelipeds, which 

 Lockington in his later description of the same speci- 

 men was inclined, in opposition to his previous opinion, 

 to regard as the larger member. Both hands in this 

 species are elongated much like the smaller hand in 

 heterochelis and, from a superficial comparison, Lock- 

 ington probably concluded that his specimen was a 



i Proc. Acad. Nat. Sci. Phila., 1887, p. 329. 



