CANCRID^ 39 



Key to Species of the Genus Cancer Examined. 

 (Young of 20 mm. and less in width.) 



a. Front markedly produced, formed of 5 subequal teeth, of which the 

 median is the most advanced; antero-lateral teeth never spiny 

 pointed; carapace never pubescent. C. productus 



aa. Front not markedly produced, formed of 5 unequal teeth, the outer 

 teeth larger and more widely separated from the three median 

 teeth than these from each other; antero-lateral teeth spiny- 

 pointed ; carapace generally pubescent. 

 b. Tenth antero-lateral tooth (counting that next the eye as one) 

 prominent, usually spiny pointed. 

 c. Carpus of cheliped with 2 prominent spines (not counting that 

 at hinge) one above at distal end, and the second be- 

 low it at inner angle. 

 d. Tenth antero-lateral tooth projecting laterally beyond 

 carapace as seen from above ; carapace compara- 

 tively smooth. C. gracilis 

 dd. Tenth antero-lateral tooth projecting dorsally, not 

 reaching beyond outline of carapace as seen from 

 above; carapace markedly areolated. 



C. gibbosulus 



a^ cc. Carpus of cheliped with a prominent spine above at 



distal end; below this at inner angle an in- 

 conspicuous spine sometimes present. Under 

 parts usually with red markings, 

 [^' " C.antennarius 



bb. Tenth antero-lateral tooth absent or represented by a rudiment. 

 c. Carapace finely pubescent, antero-lateral teeth alternately 

 large and small ; carpus of cheliped with 2 spines, one 

 above at distal end and a second less conspicuous spine 

 below this at inner angle. C. jordani 



cc. Carapace smooth or sparsely and coarsely pubescent, antero- 

 lateral teeth alternately large and small only in very 

 young specimens (5 mm. or less) ; carpus of cheliped 

 with a spine above at distal end and only in very young 

 a second minute spine below this at inner angle. 



C. anthonyi 



