CANCRHXE 37 



characters, as pointed out by Miers (Proc. Zool. Soc. London, 1879, p. 34) 

 in speaking of that genus, indicate an undoubted relationship with Tel- 

 messus and Erimacrus, so that the placing of these troublesome genera in 

 the Cancridae, as is done by Miss Rathbun, is distinctly supported by the 

 facts at hand. That gibbosulus is a Cancer there can be no doubt, in fact 

 on the basis of youthful characters it might easily be considered the most 

 typical of all the Pacific Coast species.* 



It is unfortunate that no young specimens of oregonensis were avail- 

 able, as light might have been thrown on the relationship of this interest- 

 ing form which differs so widely from other Cancers. As before men- 

 tioned, the young of productus, even in the smallest specimens at hand 

 6 mm. wide show no pubescence and no spiny tips or alternate arrange- 

 ment of the antero-lateral teeth. The antennae, though proportionally 

 larger than in the adult, are not so large as in the other species and are 

 not bushy; the front moreover retains its characteristic appearance and 

 does not resemble that of any other species examined. Its relation to 

 the other west coast Cancers would, therefore, appear to be rather distant. 



KEY TO SPECIES OF CANCER FOUND ON WEST COAST. 



a. Antero-lateral and postero-lateral margins meeting at a distinct angle; 

 carapace widest at 9th (sometimes 8th) tooth. 9, 10 or n teeth. 

 b. Front markedly produced, formed of 5 subequal teeth. 



C. productus 



bb. Front not markedly produced, formed of 5 unequal teeth ; outer 

 teeth larger and more widely separated from the 3 median 

 teeth than these from each other. 



c. Antero-lateral teeth low (projecting less than 1-3 the length 

 of base) or irregular, not spiny-pointed; fingers of 

 chelipeds not dark-tipped; merus of outer maxilliped 

 elongated, rounded anteriorly. (These characters, ex- 

 cept those of the fingers of chelipeds, do not hold in 

 very small specimens.) 



* As this paper is going to press I find an article by J. T. Cunningham in the 

 Proceedings of the Zoological Society of London (1898, p. 204) in which he figures 

 an early stage of the common European Cancer (C. pagurus) and points out the 

 close relationship to the young of Atelecydus which he considers should be included 

 in the Family Cancridae. The figure of the youngest shows the alternation of large 

 and small antero-lateral teeth mentioned above as characteristic of most species. 

 This seems to furnish an additional proof of the wisdom of extending the genus 

 Cancer. 



