LAMELLIBEANCHIATA OF THE LOWER MAELS. 107 



side of the beak. The ligamental pit has been of moderate size, but well 

 marked and deep. A single cast of this species was found in the collection 

 of Princeton College, labeled L. protexta Grabb in a handwriting which I 

 supposed to be Mr. Conrad's. The cast differs materially from that of L. 

 protexta Gabb, as given on Plate XLVIII, Fig. 23 (24), Jour. A. N. Sci., 

 Vol. IV, in the proportional length of the shell and the narrow posterior 

 extremity, but corresponds very well with that figured afterwards on Plate 

 LXVIII, Fig. 36, from Tennessee; consequently I have deemed it proper 

 to separate it under a distinct name. 



Formation and locality, — In the Lower Green Marls at Freehold, New 

 Jersey. 



Nuculana long;ifrons. 

 Plate XI, Figs. 16 and 17. 



Leda longifrons ConTad. J. A. N. S., Phil., 2d ser., Vol. Iv, p. 281, PL XL VI, Fig. 18. 



Gabb, Synop., p. 133. 

 Nuculana longifrons (Con.). Meek, Check-list, p. 8. 



Shell of moderate size, transversely subelliptical or subovate in form, 

 a little narrower behind than in front of the beaks. Beaks very small and 

 inconspicuous, situated rather more than one-third of the entire length from 

 the anterior end of the valve. Cardinal margin very gently decUning on 

 each side of the beaks; anterior end rounded, longest above the middle of 

 the heiglit; posterior end more narrowly rounded, longest just below the 

 extremity of the hinge; basal line very gentl}^ curved in the middle and 

 more abruptly so toward the extremities. Surface of the shell polished, 

 but marked by extremely fine concentric strise of growth. In the interior 

 the hinge-line is marked by proportionally long curved teeth; those on the 

 anterior side being largest and numbering fifteen or twent}^, those of the 

 posterior side very small and numerous. 



The largest individual of the species which I have seen measures about 

 one inch and a quarter in length. It is very imperfect, however, and too 

 poor for illustration. The species ma}^ be recognized by the great height 

 of the shell across the posterior extremity, and by the almost regularl}' 

 elliptical form of the valve and absence of the recurving of the posterior 

 side, as in most species of the genus. None of the five individuals before 



