EXPLANATION OF PLATE XXXVII. 



Figs. 1-7. SPIRIFER MARIONENSIS Shumard p. 30.S 



1-5. Pedicle, brachial, anterior, posterior and lateral views of a 

 nearly perfect specimen. (W. M., No. 6700.) 



Louisiana limestone, Clarksvillc, Missouri. 



6. View of a pedicle valve with much extended hinge-line. (W. 

 M., No. 13335.) 7. Brachial view of a specimen with very 

 short hinge-line. (W. M., No. 6694.) 



Louisiana limestone, Louisiana, Missouri. 



Figs. 8-17. SPIRIFER VERNONENSIS Swallow p. 310 



8-12. Posterior, pedicle, brachial, anterior and lateral views of a 

 very perfect specimen. 13. View of a large pedicle valve. 

 (W. M., No. 4686.) 



Fern Glen formation, near Kiminswick, Missouri, 

 14-17. Pedicle, brachial, anterior and posterior views of a nearly 

 perfect specimen. (W. M., No. 13535.) 



Fern Glen formation, Fern Glen, Missouri. 



Figs. 18-21. SPIRIFER OSAGENSIS Swallow p. 314 



18-19. Views of two imperfect pedicle valves. 20. View of a 

 brachial valve. (W. M., No. 13545.) 



Hannibal sandstone, Louisiana, Missouri. 

 21. View of a brachial valve. (W. M., No. 5957.) 

 Northvicw sandstone, Northview, Missouri. 



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