EXPLANATION OF PLATK XII. 

 DioNB Sayana Courad (p. 75). 



Fig. 1. A copy of Conrad's ligiire of this species, nothiug but fragiiienls of the. cardinal portion 

 being obtained from New Jersey, too poor for illustration. 



Mekcenaria cancellata Gabb (p. 68). 



Figs. 2,3. View of the interior, the binge imperfect, and of the exterior of the type specimen of the 

 species, none other having been obtained. 



Mekcenaria plena Conrad (p. 69). 



Figs. 4,5. Exterior and interior of a right valve. 



6. Anterior profile view of the valves in conjunction. 



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