MIOCENE MOLLUSCA AND CKUSTACEA. (J5 



stated by Conrad. In the North Carolina specimens this feature is much 

 more pronounced. These features and differences are so marked that were 

 there more individuals showing- constant characters I should be inclined to 

 doubt their specific identity. 



The shells belong to the collection of the Academy of Natural Sciences, 

 Philadelphia. 



Family CH AMIDES. 

 Genus CHAM A Linnaeus. 



CHAMA CONGREGATA. 



PI. ix v figs. 14-18. 



Chama congregata, Conrad; Am. Jour. Sci., vol. 23, first ser., p. 341; Medial Tert. 

 Foss., p. 32, PL xvn, fig. 2; Tuoiney and Holmes, Pli. Foss. S. Car., p. 23, PL vn, 

 figs. 7-10; Conrad's List of Miocene Foss. Atlantic Slope, p. 576; Meek, Check 

 List, Smith. Inst., p. 8, etc. 



• Shell small, dextrally coiled, lower valve deep, subangular along the 

 umbonal ridge; upper valve depressed convex, surface of the shell strongly 

 lamellose, the lamellae often expanded into moderately wide fringe-like leaves, 

 and marked by numerous small radiating plicae, which are most distinct on 

 the expanded portions of the lamellae, where they often form subspinose 

 processes or small granulose expansions, especially near the spine. The 

 radiating plicae, on the upper valve, are generally finer and more crowded 

 than on the other valve, and the lamellae more erect and exsert, Muscular 

 imprints large and distinct, very slightly elevated above the general surface 

 of the interior, and distinctly striated. Margins of the valves finely crenu- 

 lated. 



This species does not differ from C. corticosa, Conrad, in any essential 

 feature, other than in being coiled in the opposite direction. Where they are 

 found associated this one is usually somewhat smaller, but many of the New 

 Jersey specimens attain a very fair size as compared with those of C. corti- 

 cosa. 



Localities : At Shiloh, Jericho, and other places in Cumberland County, 

 N. J., and in Maryland, Virginia, and the Carolina s abundantly. Collec- 

 tions at Rutgers College and the National Museum, at Washington. 

 mon xxiv 5 



