MAEYLAND GEOLOGICAL SURVEY 657 



Superfamily CARDITACEA 

 Family CARDITIDAE 



Genus VENERICARDIA Lamarck 

 [Syst. des Anim. sans Vert., 1801, p. 123 J 



Type. Venericardia imlricata Lamarck. 



Shell closed; rounded, trigonal or cordate; umbones anterior, prosogy- 

 rate; lunule small but deep; escutcheon narrow and elongate; sculpture 

 dominantly radial; ligament external, opisthodetic, parivincular ; hinge 

 dentition in the right valve consisting of three oblique cardinals ; in the 

 left valve of two; laterals of both valves absent or very feeble; muscle 

 impressions strongly defined; pallial line entire; inner margins crenate. 



The genus was initiated in the Cretaceous; the Eecent representatives 

 are, for the most part, inhabitants of cooler waters. 



VEXERICARDIA ? INTERMEDIA (Whitfield) 



Cardita intermedia Whitfield, 1885, Mon. U. S. Geol. Survey, vol. ix, p. 209, 



pi. xxviii, figs. 14, 15. 

 Cardita intermedia Weller, 1907, Geol. Survey of New Jersey, Pal., vol. iv, 



p. 565, pi. Ixii, figs. 6-8. 



Description. " Form of cast transversely elliptical, or transversely 

 ovate, exclusive of the beaks, largest at the posterior end. Valves very 

 ventricose, with strong projecting beaks, which in this condition are 

 moderately distant. Hinge line arcuate. Anterior end narrowly rounded ; 

 posterior end more broadly rounded; basal margin strongly curved, 

 muscular scars on the cast small but distinct; margin of the cast showing 

 indications of ten or twelve rather strong radiating ribs between the 

 muscular scars. This is a very ventricose form, and has had strong, 

 enrolled, subanterior beaks, which have been directed slightly upwards as 

 well as forward." Whitfield, 1885. 



The form referred to this species is an inside cast to which a bit of the 

 shell substance still adheres in the umbonal region. It seems a trifle more 



Etymology: So-called because of a supposed combination of the characters 

 of Venus and Cardium. 



