EXPLANATION OF PLATE LXIV. 



Figs. 1-4. SPIRIFERELLA PLENA (Hall) p. 412 



1-2. Anterior and lateral views of the nearly perfect specimen 

 shown on Plate LXIII, Figs. 5-7. (W. M., No. 7053.) 



Burlington limestone, Quincy, Illinois. 



3-4. Posterior and pedicle views of a nearly complete internal 

 cast. (W. M., No. 13554.) 



Residual chert, Sedalia, Missouri. 



Figs. 5-9. SPIRIFERELLA NEGLECTA (Hall) p. 415 



5-8. Pedicle, lateral, brachial and anterior views of a small hut 

 nearly complete specimen. (W. M., No. 8616.) 



Kcokuk limestone, Edwardsville, Indiana. 



9. View of a nearly perfect internal cast of a pedicle valve, show- 

 ing the elongate dental lamellae. (W. M.. No. 5650.) 

 Residual chert, Springfield, Missouri. 



144 



