LAMELLIBRANCHIATA FROM THE MIDDLE MAEL BEDS. 197 



MYTILID^. 



Genus MODIOLA Lam, 



Modiola ovata. 



Plate XXVI, Fiys. 13 and 14. 



Modiola ovata Gabb. Jour. Acad. Nat. Sci., Phil., 4, uew ser., p. 396, PI. LXVIII, Fig. 



31. Synopsis, p. 143. Meek, Checklist, p. 11. 

 Perna ovata (Gabb) Meek. Geol. Surv. N. J., 1808, p. 726. 



Shell ovate in outline, or elong'ate ovate, of about a medium size, some- 

 vi'hat alate at the extremity of tlie short hinge-line. Valves very ventricose, 

 with nearly terminal beaks, which are small, incurved, and not conspicu- 

 ously raised above the cardinal line. Umbonal ridge ]5rominently rounded, 

 and the surface of the shell in front of it slightly sinuate, giving a slight 

 sinuosity to the basal line; posterior extremity of the shell broadl3' rounded, 

 and the anterior end narrow. Surface of the shell marked by very fine, 

 obscure lines of growth. 



Formation and locality. — In the Middle Marl Bed, at Timber Creek, 

 New Jersey. 



Genus MODIOLA Lam. 



Modiola (Lithodomus ?) inflata, u. sx). 



Plate XXVI, Figs. 1 and 2. 



Shell small, cylindrically ovate, with large, tumid, anterior beaks, and 

 parallel dorsal and basal margins. Anterior and posterior ends nearly 

 equally rounded in a general view, as the beaks, from their downward 

 direction of curvature as seen in a lateral view, are blended with the 

 anterior margin so nearly as to give almost the same form as the posterior 

 end. In a dorsal view the form is strongly cuneately ovate from the rapid 

 attenuation of the shell posteriorly. Hinge-line rather short and the liga- 

 ment slender. 



This species bears considerable resemblance to Modiola Johnsoni, but 

 never attains so great a size, is more cylindrical, with a differently formed 

 beak, and a different surface structure, being smoother and destitute of the 



