160 PALEONTOLOGY OF NEW JEESEY. 



his species the form which is most erect, as corresponding most nearly to it. 

 In this respect it is most nearly allied to (7. spissa Conrad, although that 

 one is longer in an antero-posterior direction than any of the specimens 

 referred to C. excavata. 



Formation and locality. — In the Lower Green Marls at Holmdel and 

 elsewhere in Monmouth County, New Jersey. Dr. Morton's specimen was 

 from Arneytown, New Jersey. 



Cyprimeria Heilprini, d. sp. 

 Plate XXII, Figs. 14 and 15. 



Shell of medium size, transversely elliptical in outline, and very decid- 

 edly inequivalve, but nearly equilateral, as seen in the condition of inter- 

 nal casts. Beaks prominent and nearly or quite central. Right valve 

 much the most convex, and the left .concave toward the front, giving a 

 decided curvature to the basal line as seen on the edge of the cast. Mus- 

 cular scars large and well marked ; no pallial sinus. The hinge-plate has 

 been quite thick, and the teeth large and strong, as evinced by the broad 

 depression along the cardinal line of the cast. Surface features unknown. 



This species has somewhat the external form of C appressa Conrad, 

 but has been a much deeper or more ventricose shell, with proportionally 

 more elevated and prominent beaks. It is also somewhat related in form 

 to (7. densata, but is proportionally more transverse and more equilateral 

 than any specimen of that species observed. Although I have seen but a 

 single individual cast of it, the features are so marked and prominent, that 

 I have not hesitated to describe it as a distinct form. 



Formation and locality. — In the lower beds of the Lower Green Marls at 

 Crosswicks, New Jersey. From the collection of the Academy of Natural 

 Sciences of Philadelphia. 



Cyprimeria spissa. 

 Plate XXII, Fig. 18. 



Cyprimeria spissa Conrad. Am. Jour. Conch., Vol. Y, p. 44, PL I, Fig. 9. 



The specimen figured in this report is the only one which I have seen 

 that will in any degree correspond to the figure given by Mr. Conrad of his 



