MOLLUSCA. 421 



1868. Pinna rostriformis Con., Cook's Geol. N. J., p. 725. 

 1886. Pinna rostriformis Whitf., Pal. N. J., vol. i (Monog. U. 



S. G. S., vol. 9), p. 198, pi. 16, figs. 3-4. 

 1905. Pinna rostriformis Johns., Proc. Acad. Nat. Sci. Phil. 



(1905), p. 10. 



Description. — When complete the shell attains a length of 80 

 mm. or more, with a height of 32 mm. or more. Shell elongate 

 triangfular in form, with an attenuated, pointed anterior ex- 

 tremity ; the beak anterior. Hinge-line straight, nearly equaling 

 the total length of the shell ; basal margin broadly concave in the 

 anterior third of its length, becoming gently convex posteriorly ; 

 posterior margin broadly rounded, the dorsal portion extending 

 farther fo'rward than the ventral. Valves ventricO'Se, subangular 

 along the median line of the shell. The upper two^thirds of the 

 surface marked by rather strong radiating costse ; the entire sur- 

 face marked by concentric lines oif growth, and by undulations 

 which become stronger upon the lower non-radiate portion of 

 the shell. 



Remarks. — This species has only been observed in a more or 

 less fragmentary condition. It resembles P. laqweata, but is. more 

 slender in front, with the anterior portion of the ventral margin 

 decidedly concave. 



Formation and locality. — Vincentown limesand, Cookstown 

 (151), Timber Creek (Whitfield ) . 



Geographic distribution. — New Jersey. 



Family PERNIDAB. 

 Genus Gervii,IvIOpsis Whitfield. 



Gervilliopsis ensiformis (Conrad). 



Plate XXXVIL, Figs. 4-5 ; Plate XXXVIIL, Figs. 1-3. 



1858. Gervillia ensiformis Con., Jour. Acad. Nat. Sci. Phil., 



2nd sen, vol. 3, p. 328, pi. 34, fig. 10. 

 1861. Gervillia enMformis Gabb, Synop. Moll. Cret. Form., p. 



180 (114). 

 1864. Gervillia ensiformis Meek, Check List Inv. Foss. N. A., 



Cret. and Jur., p. 9. 



