20 CALIFORNIA ACADEMY OF SCIENCES. 



the male. Speaking of a collection of specimens of this 

 species from Vancouver's Island, Professor Smith says: 

 ''The series of specimens is sufficient to show that the 

 two forms described by Dana are sexual and belong to 

 one species, the gracilis being based on the adult male, 

 and the hirta on the two forms of the female. In the 

 characters of the rostral spines and the rest of the cara- 

 pax, all the larger males before me agree with the 

 description and figures of gracilis, while in the same 

 characters the females agree with hirta, and the smaller 

 males are more or less intermediate between the two 

 forms. But among the females themselves there are 

 two forms: all the adult and fertile specimens having 

 the abdomen very broad, and nearly orbicular, while in 

 the other specimens (most of them small, but some of 

 them as large as the smaller of those with orbicular 

 abdomens) the abdomen is much narrower and elliptical, 

 as shown in Dana's fig. 3, 6. The smaller of these latter 

 females are, perhaps, merely immature individuals, but 

 the larger are truly dimorphic, sterile females, such as 

 are found in many genera of Brachyura, and here, as in 

 most similar cases, the larger of the sterile individuals 

 show considerable approach to the males in the form of 

 the carapax, etc. 



"In the largest male before me the merus of the cheli- 

 peds reaches nearly or quite to the tip of the rostrum^ 

 and, in this respect, agrees with Bate's 0. longimana,. 

 though the chelipeds are not nearly twice as long as the 

 carapace, if the rostrum is, as it is usually, included in 

 the length." 



Genus Erileptus Rath. 



Carapax broadly triangular; regions well defined, convex. There is a 

 postorbital and also a supraorbital spine. Eostrum slender and sim- 

 ple. Abdomen and sternum granulate; abdomen six-segmented. Basal 



