Figs. 19-20. ORBICULOIDEA BATESVILLENSIS Weller p. 42 



Views of the internal casts of two brachial valves, the cotypes. 

 (W. M., No. 4963.) 



Batesville sandstone, Batesville, Arkansas. 



Figs. 21-22. ORBICULOIDEA SAMPSONI (Miller) p. 40 



21. View of a brachial valve, the holotype. (W. M., No. 6962.) 

 22. View of another brachial valve. (W. M., No. 9674.) 

 Chouteau limestone, Sedalia, Missouri. 



Figs. 23-24. ORBICULOIDEA VARSOVIENSIS (Worthen) p. 41 



Views of the cotypes. 24. A nearly complete pedicle valve from the 

 inner side. 23. Two much crushed valves upon a fragment of 

 limestone. (I. S. M., No. 2545.) 



Keokuk limestone, Warsaw, Illinois. 



Figs. 25-26. CRANIA REPOSITA White p. 44 



25. View of four specimens of pedicle valves attached to a shell of 

 Spirifer grimesi. 26. View of a fourth individual from another 

 portion of the same -S\ grimesi. Cotypes. (U. M., No. 1692.) 

 Burlington limestone, Burlington, Iowa. 



Figs. 27-29. CRANIA CHESTERENSIS Miller & Gurley p. 45 



Views of the cotypes, attached to the bases of the bryozoan Lyrio- 

 pora, and to a shell of Spirifer. (W. M., No. 6067.) 

 Chester beds, Chester, Illinois. 



Fig. 30. CRANIA MISSOURIENSIS Weller p. 43 



Exterior view of a brachial valve, the holotype. (W. M., No. 

 13902.) 



Fern Glen formation, Fern Glen, Missouri. 



Fig. 31. CRANIA SPICULATA Rowley p. 47 



View of a brachial valve, the holotype. (R. R. R.) 

 Louisiana limestone, Louisiana, Missouri. 



Fig. 32. CRANIA DODGEI Rowley p. 44 



View of a brachial valve, the holotype. (R. R. R.) 

 Louisiana limestone, Louisiana, Missouri. 



Fig. 33. CRANIA L,EVIS Keyes p. 47 



View of a brachial valve, one of the cotypes. (R. R. R.) 

 Burlington limestone, Louisiana, Missouri. 



Figs. 34-36. CRANIA BLAIRI Miller p. 46 



34-35. External and internal views of a brachial valve. (W. M., 

 No. 9675.) 36. View of a large brachial valve. (W. M., No. 

 14310.) 



Chouteau limestone, Pettis County and Providence, Mis- 

 souri. 



Figs. 37-39. CRANIA ROWLEYI Gurley p. 46 



View of a brachial valve, the holotype. (W. M., No. 6316.) 

 38-39. Views of two other brachial valves. (W. M., Nos. 11895 

 and 13060.) 



Louisiana limestone, Louisiana, Missouri. 



