PLATE XVI— Continued. 



Genus CHONETES, Fischer ok AValdiieim. 



Page 303. 



Chonetes Verneuiliana, Norwood and Pratteu. 



Figs. 20, 21. Two views ; showing- the strong' median constriction. X '-. 

 Coal Measures. Illinois. 



Chonetes mesoloba, Norwood and Pnitten. 

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

 Coal Measures. lUhiois. 



Chonetes concentrica, de Koniuck. 



Fig. 23. A species in which the surface is covered with strong concenti-ic wrinkles. This species may not 

 prove congeneric with Chonetes striatella, Dalman. 



Lower Carboniferous limestone. Vise, Belgium. 



Chonetes Logani, Norwood and Pratteu. 



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 defxecta, Hall. 



Fig. 28. The interioi- of a brachial valve. X 2. 



Hamilton group. Western New York. 



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 coronala, 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 York. 



Genus STROPHEODONTA, Hall. 



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

 Page -.'St. 



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. 



