PLATE XVI— Continued. 



Genus CHONETES, Fischer de Waldheim. 



Page 303. 



Chonetes Verneuiliana, Norwood and Pratten. 

 Fig3. 20, 21. Two views ; showing- the strong median constriction. X 2. 

 Coal Measures. Illinois. 



Chonetes mesoloba, Norwood and Pratten. 



Fig-. 22. A pedicle-valve ; showing the median fold. X 2. 

 Coal Measures. Illinois. 



Chonetes concentrioa, de Kouinck. 



Fig. 23. A species in which the surface, is covered with strong concentric wrinkles. This species may not 

 prove congeneric with Chonetes striatella, Dalman. 



Lower Carboniferous limestone. Fj.se, Belgium. 



Chonetes Logani, Norwood and Pratten. 



Fig. 25. The interior of a brachial valve ; showing the brachial ridges. Drawn from a gutta-percha im- 

 pression. X 2. 



Waverly group. Wayne county, Ohio. 

 See Part ii. Volume VIII, for further illustration. 



Chonetes deelecta, Hall. 



Fig. 28. The interior of a brachial valve. X 2. 



Hamilton group. Western New Twk. 



Chonetes lineata, Conrad. 

 Fig. 34. The interior of a pedicle-valve ; showing the area, teeth and muscular impressions. X 2. 

 Corniferous limestone. Western New York. 



Chonetes syrtalis, Conrad ( ^ C coronata, Conrad). 

 Fig. 39. An internal cast of the brachial valve ; showing the brachial ridges. 

 Fig. 41. An internal cast of the pedicle-valve. 

 Fig. 43. An impression of the exterior of a large shell. 



Hamilton group. Eastern New YoQ'k. 



Genus STROPHEODONTA, Hall. 



(See Plates XIII, XIV, XV, XVe, XX.) 

 Page 284. 



Stropheodonta callosa, Hall. 



Fig. 37. An enlarged cardinal view of the pedicle-valve ; showing the muscular impressions and crenula- 

 tions of the area. 



Schoharie grit. Near Clarksville, N. Y. 



