CANCROIDEA. 



CANCER DENTATUS (Bell). 

 Valparaiso. 



Length of carapax of a male, in this hairy species, two inches; 

 greatest breadth, two and seven-eighths inches; making the ratio 

 of length to breadth 1 : 144. The figure by Bell affords the ratio 

 1 : 1-57. In his figure, the sides of the carapax are not as broadly 

 rounded as in our specimens; which hardly make an approach to an 

 angle at the last of the prominent teeth. The medial region is dis- 

 tinct in its outline, and 3 M and 2 M separate. The antero-lateral 

 region has imperfectly the usual areolation, 5 L and 6 L being faintly 

 separate, and 2 L also somewhat distinct. The ten triangular teeth 

 of the margin appear to correspond, the first to D; the second and 

 third to E; the fourth and fifth to N; the sixth, seventh, and eighth to 

 T; the ninth to S; and the tenth is a posterior tooth. The areola 

 1 P is somewhat rhombic, a little oblong, and well defined. 



Cancer dentatus, BELL, Zool. Trans., i. 339, pi. xlv., 1835. 

 Cancer polyodon, PcEPPIG, Wiegm. Arch., 1836, p. 133. 



CANCER PLEBEIUS, Poeppig. 

 Valparaiso. 



Length of carapax of one specimen (male), two and three-fourths 

 inches; greatest breadth, four and five-eighths inches; ratio of length 

 to breadth, 1 : T67. A young male gave for the length, S'l lines; 

 breadth, thirteen lines; ratio of length to breadth, 1 : 1-6. The 

 regions are mostly indistinct, but may be partly distinguished ; Bell's 

 figure fails of representing what actually appear. They are in 

 general very nearly as in the Edwardsii, and the ten lobes of the 

 antero-lateral margin have the same relations. 



The Cancer irroratus of Say is recognised by Dr. A. A. Gould as a 

 distinct species from the C. irroratus of Bell, in his Report on the 

 Invertebrata of Massachusetts, 1841, and is named Cancer /Sayi. But 



