UNIONIDJ3 FROM TBE OAMDEN CLAYS. 247 



Lea's descrijjtion (length 2.6, breadth 3.4 inches) are evidently transposed 

 from what he intended, the length being nearly three and a half and the 

 height two and six-tenths inches, as will readily be seen by reference to the 

 jfigure given, which is of his type specimen. 



Unio cariosoides. 

 Plate XXXII, Fig. 3. 

 Unio cariosoides Lea. Proc. A. N. Sci., Phil., 1868, p. 163. Pamphlet by Lea, p. 31. 



" Shell smooth, broadly elliptical, somewhat inflated, obtusely angular 

 behind, rounded before ; beaks somewhat raised, removed from medial ; 



cardinal teeth ; lateral teeth long and slightly curved. Length 2.5, 



breadth 4.8 inches." (Lea.) 



Mr. Lea's type specimen is the only one of this species which I have 

 .seen. As he observes in his remarks following the above description, it 

 rather closely resembles the elongated males of U. cariosus. The specimen 

 has apparently been imbedded in the clay vertically and has been slightly 

 compressed in that direction, making it a little less broad between the car- 

 dinal and basal margins than it originally was, and giving greater angu- 

 larity to each of the extremities, and at the same time greater rotundity 

 to the valves. If this had not been the case the shell would present much 

 the same proportions as those which I have referred to U. radiatoides, al- 

 though it may never have been quite as high in proportion to its length. 

 The specimen is mostly an internal cast, but retains a small portion of the 

 epidermal layer, as do most of the specimens. The impressions of the lat- 

 eral teeth are slender, rather long and arcuate. What remains of the bor- 

 -ders of the cavity of the cardinal teeth would indicate that the principal 

 one had been large and thick, but there is very little of it left to judge from. 

 The anterior muscular impression is large, and situated well forward. The 

 posterior scar is not visible. The pallial line on the anterior half is well 

 marked. In the measurements as given by Dr. Lea the "length" refers to 

 the distance from the cardinal line to the basal margin, and the "breadth" 

 from anterior to posterior extremity. The locality for this and U. suhro- 

 tundoides, as given on the labels accompanying them, is 6 miles north of 

 Camden, New Jersev. 



