EXPLANATION OF PLATE XXXIX. 



Figs. 1-10. SPIRIFER PLATYNOTUS n. sp p. 317 



1. View of a pedicle valve. 2. View of a brachial valve. (W. M., 

 No. 6674.) 3-5. Views of three pedicle valves. 6. View of a 

 brachial valve. Cotypes. (W. M., No. 13544.) 

 Kinderhook, Bed No. 6, Burlington, Iowa. 



7-10. Pedicle, brachial, anterior and lateral views of a nearly per- 

 fect specimen probably belonging to this species. (W. M., 

 No. 7502.) 



Kinderhook, Bed No, 5, Burlington, Iowa. 



Figs. 11-23. SPIRIFER MISSOURIENSIS Swallow p. 319 



11-14. Posterior, lateral, pedicle and brachial views of a nearly per- 

 fect example showing the distinct fasciculation of the plications. 

 (W. M., No. 10719.) 



Chouteau limestone, Pettis County, Missouri. 



15-18. Pedicle, brachial, anterior and posterior views of a nearly 

 perfect specimen. 19-23. Posterior, lateral, pedicle, brachial 

 and anterior views of a large specimen somewhat restored at the 

 cardinal extremities. (W. M., No. 9663.) 



Chouteau limestone, Chouteau Springs, Missouri. 



Figs. 24-26. SPIRIFER BIPLICATUS Hall p. 320 



24-25. Views of two internal casts of pedicle valves. 26. View of 

 the internal cast of a brachial valve. (W. M., No. 5931.) 

 Chonopectus sandstone, Burlington, lozva. 



Figs. 27-30. SPIRIFER BIPLICOIDES n. sp p. 323 



27. View of a plaster cast of the pedicle valve from a natural 

 mould. 28. View of the internal cast of a brachial valve. 

 (W. M., No. 6660.) 29. View of a plaster cast from a natural 

 mould of the pedicle valve. (W. M., No. 14785.) 30. View of 

 the internal cast of a brachial valve. (W. M., No. 14755.) 

 Kinderhook, Bed No. 5, Burlington, Iowa. 



94 



