EXPLANATION OF PLATE XXX. 



Figs. 1-6. RHYNCHOPORA PERSINUATA (Winchell) p. 233 



1. View of an internal cast of a pedicle valve. The holotype. 

 (U. M., No. 1998.) 2. Anterior view of a large internal cast, 

 imperfect posteriorly. (W. M., No. 6712.) 



Kinderhook, Bed No. 7 , Burlington, Iowa. 



3-4. Brachial and lateral views of a nearly complete specimen. 

 5-6. Pedicle and anterior views of another specimen. (D. K. 

 G., No. 1302.) 



Lake Valley beds, Lake Valley, New Mexico. 



Figs. 7-15. RHYNCHOPORA? COOPERENSIS (Shumard) p. 235 



7-11. Pedicle, brachial, lateral, anterior and posterior views of a 

 nearly complete specimen. (W. M., No. 9661.) 



Chouteau limestone, Chouteau Springs, Missouri. 

 12-15. Pedicle, brachial, lateral and anterior views of a nearly com- 

 plete specimen. (R. R. R.) 



Burlington white chert, Louisiana, Missouri. 



Figs. 16-17. RHYNCHOPORA sp. 



16. View of a pedicle valve. (W. M., No. 6716.) 



Burlington limestone, Burlington, Iowa. 



17. View of a brachial valve probably belonging to the same species. 

 (W. M., No. 13958.) 



Burlington limestone, Springfield, Missouri. 



Figs. 18-21. RHYNCHOPORA? ROWLEYI n. sp p. 237 



Pedicle, brachial, anterior and lateral views of a very perfect speci- 

 men. (R. R. R.) 



Louisiana limestone, Louisiana, Missouri. 



Figs. 22-25. RHYNCHOPORA? COOPERENSIS (Shumard) (?) p. 235 



Pedicle, brachial, posterior and lateral views of a somewhat crushed 

 specimen. (W. M., No. 8548.) 



Pierson limestone, near Springfield, Missouri. 



Figs. 26-29. CENTRONELLA LOUISIANENSIS n. sp p. 241 



26-27. Pedicle and brachial views of a very perfect shell (x4). 

 28-29. Pedicle and brachial views of another example (x4). 

 (W. M., No. 6730.) 



Louisiana limestone, Louisiana, Missouri. 



Figs. 30-33. TRIGERIA ? CURRIEI (Rowley) p. 245 



30-31. Pedicle and brachial views of a very perfect shell (x4). 

 32-33. Pedicle and brachial views of another specimen (x4). 

 (W. M., No. 6732.) 



Louisiana limestone, Louisiana, Missouri. 



Figs. 34-39. SELENELLA PEDICULUS (Rowley) p. 244 



34-35. Pedicle and brachial views of a very perfect specimen (x4). 

 36-37. Similar views of another specimen (x4). 38-39. Similar 

 views of a third example (x4). (W. M., No. 6731.) 

 ^Louisiana limestone, Louisiana, Missouri. 



69 



