LAMELLIBRANCHIATA OF THE LOWER MARLS. 135 



collection at Rutgers College, New Brunswick, while Mr. Conrad's speci- 

 mens were from Haddonfield, New Jersey, near Philadelphia. All of these 

 localities are in the Lower Green Marls. 



Cardium (Criocardium) multiradiatum. 

 Plate XXI, Figs. 1-3. 



Cardium multiradiatum Gabb. Jour. A. N. Sci. Phil., 2d series, Yol. lY, p. 395. 

 Criocardium multiradiatum (Gabb) Conrad. Am. Jour. Conch., Yol. YI, p. 75, PI. 

 LXYIII, Fig. 29. Meek, Check-list, and Catal. in Geol. Eept. K. J., 1863. 



Shell globularly ovate, extremely ventricose and cordate, with large, 

 prominent, nearly erect beaks, which are strongly incurved but moderately 

 distant in the casts, valves gibbously convex and perceptibly more promi- 

 nent, but not angular along the posterior umbonal region ; the posterior slope 

 being perceptibly more abrupt than the opposite side of the valves. Basal 

 margin of the shell rounded, the posterior side perceptibly more straight- 

 ened and the anterior round; the whole valve being very slightly oblique. 

 Muscular imprints large but not strong ; cardinal tooth, as indicated by the 

 imprint left on the valve, large and strong; lateral tooth unknown; inner 

 margin of the shell crenulate, and slightly marked for a very.short distance 

 by the ribs. The exterior surface, which I have supposed to belong to this 

 shell, as indicated in a matrix, has been marked by fine, closely set, and car- 

 inate ribs, the interstices between which are characterized by closely arranged 

 and laterally compressed recurved spines, which are distant but little more 

 than their own width from each other, and are often placed on the side of 

 the rib. 



Among the specimens which have usually been referred to this species 

 from the Lower Green Marls are three very distinct species; but I have 

 retained for this one that which is most finely and closely marked, on account 

 of the signification of the specific name. Two of the forms are short- 

 ovate and the third one elongate-ovate. This species, here considered, is 

 the most ventricose of the two former, and it is also somewhat less in its 

 antero-posterior dimensions as compared with the height from the beaks to 

 the basal margin. It will be somewhat difficult to distinguish specifically 

 between them in the casts, but the surface is so very distinct that it will not 



