MOLLUSCA. 431 



may be apparent rather than real on account of imperfections in 

 the specimens. The specimen illustrated by Whitfield has the 

 posterior wing almost entirely lacking, and the anterior wing is 

 also incomplete, as it has never been observed when complete 

 with the rounded outline shown by that author. The specimens 

 from the Wenonah sand are not so large as those from the Cliff- 

 wood clay, but they agree with them in all essential respects. 



These New Jersey specimens do not seem to possess any char- 

 acteristics to distinguish them from the western shell described 

 by Evans and Shumard as Avicula linguae for mis, and that name 

 must undoubtedly be considered as a synonym of Conrad's 

 species. Some of the New Jersey specimens are more oblique 

 than the western shell as illustrated by Meek, but others possess 

 essentially the same form. 



Formation and locality. Cliffwood clay, Cliffwood Point 

 (105), near Matawan (186, 189); Wenonah sand, near Marl- 

 boro (130), near Crawfords Corner (i26 3 ). 



Geographic distribution. New Jersey, Colorado, South Da- 

 kota, Canada (N. W.). 



Pteria laripes (Morton). 

 Plate XLIL, Fig. 3. 



1834. Avicula laripes Mort., Synop. Org. Rem. Cret. Gr. U. S., 



p. 63, pi. 17, fig. 5. 

 1861. Avicula laripes Gabb, Synop. Moll. Cret. Form., p. 158 



(102). 



1864. Pteria laripes Meek, Check List Inv. Foss. N. A., Cret. 



and Jur., p. 9. 

 1886. Pteria laripes Whitf. Pal. N. J., vol. i (Monog. U. S. G. 



S., vol. 9), p. 69, pi. 14, fig. 9. 

 1905. Pteria laripes Johns., Proc. Acad. Nat. Sci. Phil. (1905), 



p. 10. 



Description. "Shell of but moderate size, oblique ovate and 

 moderately convex, with rather prominent beaks. Hinge less 

 than half the length of the body of the shell, forming on the pos- 

 terior side a proportionally large wing, which is obtusely pointed 



