MOLLUSCA. 669 



Family DBPHINULIDAE. 

 Genus DEXPHINULA Lamark. 



Delphinula navesinkensis n. sp. 

 Plate LXXV., Figs. 18-19. 



Description. The dimensions of the type specimen are: 

 height, 10 mm.; maximum diameter, 15 mm. The shell has a 

 low spire, with about two full volutions shown in the internal 

 cast, with the suture well defined and with a broad, open um- 

 bilical cavity. The first volution increases rather rapidly in size 

 but the enlargement of the outer volution is very gradual, its 

 outer portion appearing, from the cast, to be free for a short dis- 

 tance. In the. inner portion of the shell the exposed surface of 

 the volutions is rounded, but in the outer volution, especially 

 towards the aperture, a strong revolving angle is developed a 

 little above the mid-height of the volution. 



Remarks. A single nearly perfect internal cast of this species 

 has been observed, and from the cast alone its generic position 

 cannot be determined with entire satisfaction. It is evidently 

 a low-spired form with a broad umbilicus and without columellar 

 folds. 



Formation and locality. Navesink marl, near Walnford 



(149). 

 Geographic distribution. New Jersey. 



Family TROOHIDAE. 



Genus MARGARITA Leach. 



Margarita abyssina (Gabb). 



Plate LXXV., Figs. 20-22. 



1860. Solarium abyssimts Gabb, Proc. Acad. Nat. Sci. Phil. 



(1860), p. 94, pi. 2, fig. 9. 



1 86 1. Architect onica abyssinis Gabb, Synop. Moll. Cret. Form., 



P. 95 (39). 



1864. Margarita abyssinus Meek, Check List Inv. Foss. N. A., 

 Cret. and Jur., p. 18. 



