138 Cmcinnati Society of Natural History. 



pressure is oblique to the axis of the shell, it is readily detected. 

 Among those sent for identification, I find the following new forms, 

 which are sufficiently marked to be characterized as species: 



Ctpricardites quadrangularis, n. sp. (Plate VI., fig. 5.) 

 Shell rather above a medium size, somewhat quadrangular in out- 

 line and very erect, with prominent, incurved and sub-central beaks 

 which overhang the proportionally large ligamental areas. Height of 

 the shell, in the example used, slightly greater than the length in an 

 anterior and posterior direction. Cardinal line short, less than half as 

 long as the shell below. Valves moderately convex, and apparently 

 quite prominent along the distinctly' angular umbonal ridge; regu- 

 larly convex anterior to the ridge, and slightly flattened on the postero- 

 cardinal slopes. Anterior margin rounding from tlie hinge extremity 

 to the postero-basal angle, with a nearly regular curvature; and from 

 this point to the posterior extremity of the hinge has been nearly ver- 

 tical, the border having only a slightly convex outline. Surface of the 

 valves marked by closely arranged concentric lines of growth, which 

 form slight undulations of the surtace by their irregularity. 



This species differs from any other of the Genus yet noticed, in the 

 extremely erect form, prominent beaks and quadrangular aspect of 

 the outline. The example used in description has been obliquely 

 crushed, distorting the shell in such a manner as to shorten the right 

 valve on the anterior side of the umbonal ridge, and the left valve 

 on the posterior side; the entire length prol)ably having been some- 

 what reduced, while the height has not been materiall}^ changed. 

 Other individuals of the species may probably show the height and 

 length to be nearly equal, or the length may possibly slightly exceed 

 the height. The prominent beaks, elevated more than one fifth of the 

 entire height of the shell above the hinge, together with the short 

 cai'dina! line is a rather marked feature. In the general aspect, the 

 species has much the appearance of the forms referred to the genus 

 Anodontojjsis, McCoy. But the existence of a distinct and well marked 

 cardinal or ligamental area at once places it with Cypricardites. 



Formation and locality: In the soft shales of the upper part of the 

 Hudson River Group, Clinton Co., Ohio. 



CuNEAMYA cuRTA, u. sp, (Plate VI., figs. 6, 6a.) 

 Shell of medium size, rotund or sub-globose in general form, and 

 abruptl}'- cuneate posterior to the umbonal ridge when viewed from 

 above. Height and length sub-equal iu the example used, which shows 

 evidence of considerable shortening by compression. Valves very ven- 

 tricose, prominent on the umbones, with large closely incurved beaks, 

 situated very near to the anterior end of the shell, but yet not quite 



