PLATE LXXI w 



PAGK 



Figs. 1-9. SPIRIFER AREXOSUS (Conrad) 415 



1, 2. Dorsal and ventral views of a young individual. 



3-6. Dorsal, side, cardinal and anterior views of an average specimen. 



7. The spiralia silicified. 



8, 9. Exterior and interior of a large ventral valve. 



Oriskany formation, Ridgely member, Cumberland. (After 

 Hall.) 



Figs. 10-16. CYRTINA ROSTRATA (Hall) 423 



10, 11. Cardinal and side views of a large specimen. 



12. Interior of ventral valve. 



13. Dorsal valve. 



14. Anterior view of an alate specimen. 



15, 16. Dorsal and cardinal views of a small specimen. 

 Oriskany formation, New York. 



Fig. 17. SPIRIFER PROAVITUS Schuchert n. sp 418 



Dorsal view of type. Helderberg formation, New York. 



