MOLLUSCA. 419 



Remarks. — This species can be recognized by its smaller size, 

 its more elliptical form and its straighter hinge-line than any- 

 other members of the genus in New Jersey. 



Formation and locality. — Cliflwood clay, Cliffwood Point 

 (105, 185), near Matawan (107, 189); Woodbury clay, Loril- 

 lard (102), near Matawan (103); Wenonah sand, near Marl- 

 boro (130^). 



Geographic distribution. — New Jersey, North Carolina. 



Super-family PTERIACEA. 



Family PINNIDAB. 



Genus Pinna Linneus. 



Pinna laqueata Conrad. 



Plate XXXVI., Pig. i ; Plate XXXVII., Fig. i. 



1858. Pinna laqueata Con., Jour. Acad. Nat. Sci. Phil., 2nd ser., 



vol. 3, p. 328. 

 1861. Pinna laqueata Gabb, Synop. Moll. Cret. Form., p. 222 



(166). 

 1864. Pinna laqueata Meek, Check List Inv, Foss. N. A., Cret. 



and Jun, p. 9. 

 i86§. Pinna laqueata Con., Cook's Geol. N. J., p. 725. 

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



G. S., vol. 9), p. 81, pi. 16, figs. 1-2. 

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



(1905), p. 10. 



Description. — "Shell of moderate size, very rapidly expanding 

 from the apex and ventricose, giving a subquadrangular section. 

 Surface marked by from 9 to 11 strong, simple, radiating 

 ribs on the dorsal portion, which are broad and rounded on the 

 top and separated by very broad concave interspaces. The lower 

 or basal portion is marked by very strong concentric striae par- 

 allel to the margin, so very irregular as to often form strong un- 

 dulations of the surface. Line of division between the upper and 

 lower sections of the valves very strongly marked on the cast, often 

 presenting the appearance of a distinct suture. Posterior margin 



