LAMELLIBEANCHIATA OF THE LOWEE MAELS. 125 



loss of the only example, and that a borrowed one. The specimen is marked 

 on the card in Mr. Conrad's handwriting, Gouldia septenaria^ but as I can find 

 no such name in use, and as the specimen corresponds somewhat with the 

 figure and description of G, decemnaria^ I presume it to be a mistake in 

 writing the label. The figure given by Mr. Conrad is much too pointed and 

 more triangular than the shell would warrant, but in making figures so 

 small as that which he gives, these differences can hardly be avoided. 



Formation and locality, — In the micaceous clays of the Lower Marls at 

 Haddonfield, New Jersey. Borrowed from the collection of the Academy 

 of Natural Sciences of Philadelphia. 



Gouldia Conradi, u. sji. 

 Plate XVIII, Figs. 1-3. 



Shell small, the largest specimen observed not exceeding three-six- 

 teenths of an inch in its greatest diameter. Valves subtriangular, approach- 

 ing a quadrangular outline by the truncation of the posterior extremity, 

 which gives the valves when seen from the exterior much the form and 

 character of a young CrassateUa, which is also added to by their moderate 

 convexity. Beaks small and pointed. Anterior and posterior sides of the 

 cardinal margin straight, forming a little more than a right angle with each 

 other, the posterior side being nearly one-half longer than the anterior, 

 and the basal line somewhat regularly rounded. Surface of the shell 

 marked by concentric undulations, which are abruptly bent in crossing the 

 umbonal ridge. Posterior umbonal slope flattened. Lunule rather long 

 and narrow. Substance of the shell thin. Ligamental pit of the hinge 

 small in the left valve, and the posterior cardinal tooth-cavity linear and 

 extending nearly the entire length of the cardinal border. In the right 

 valve the pit is larger and the anterior lateral tooth-cavity more strongly 

 marked. . Muscular scars and pallial line distinctly marked in the right 

 valve (figured), but much less strongly so in the left one, which is thinner 

 in substance, although a slightly larger valve. 



I find no description or figure answering to this shell, and suppose it 

 to have been hitherto undescribed, although it has existed among some 

 miscellaneous material from Haddonfield, N. J., in the collection of the 



