39 



CARDITA BOREALIS. 



Tab. VIII, fig. 1. 



SPECIFIC CHARACTER. 



Shell suborbicularj thick, with about eighteen nar^ 

 row ribs, and the interstices concave and transversely 

 w rinkled ; epidermis brown black ; margin not pro- 

 foundly crenulated. 



Cabinet of the Acad. Nat. Sciences, No. 971. 



OBSERVATIONS. 



A rare shell, and if Venericardia should be still ac- 

 knowledged as a genus, it must be called F. borealis. 

 Lamarck describes but one recent species. 



The only specimen I have seen is in the collection 

 of the Academy, and was found on the coast of Mas- 

 sachussetts by Dr. C. Pickering. 



CARDITA INCRASSATA. 

 Tab. VIII, /g. 2. 



SPECIFIC CHARACTER. 



Shell oblong; ribs about 18, elevated, crenulated 

 anteriorly, an(;l marked with fulvous or brown spots. 



