EXPLANATION OF PLATE LXI. 



Figs. 1-8. BRACHYTHYRIS SUBORBICULARIS Hall p. 374 



1-2. Pedicle and brachial views of a sulphur cast of the holotype. 

 (W. M., No. 14217.) 



Keokuk limestone, Kcokuk, Iowa. 



3. View of a large pedicle valve. (W. M., No. 13409.) 4. Ped- 

 icle view of another specimen. (W. M., No. 8627.) 



Keokuk limestone, Keokuk, lozva. 



5. View of a brachial valve. (W. M., No. 385.) 6. View of 

 another pedicle valve. (W. M., No. 5655.) 



Burlington limestone, Springfield, Missouri. 



7. View of an incomplete brachial valve. 8. View of an incom- 

 plete pedicle valve. (W. M., No. 13324.) 



Crawfcrdsrillc beds, Crawfordsville, Indiana. 



138 



