PLATE LVIII 



PAGE 



Fig. 1. STROPHEODONTA (LEPTOSTROPHIA) ARCTIMUSCULA Schuchert n. sp. . 317 

 Interior of ventral valve. Oriskany formation, Shriver member, 21st 

 Bridge. 



Figs. 2-5. STROPHEODONTA (LEPTOSTROPHIA) MAGNIFICA (Hall) 318 



2. Exterior of ventral valve. 



3. View of dorsal valve. 



4. Ventral interior. 



5. Interior of dorsal valve. 



Oriskany formation, Ridgely member, Cumberland. (Figs. 

 3-5 after Hall.) 



Figs. 6-8. STROPHEODONTA (LEPTOSTROPHIA) MAGNIVENTRA (Hall) 319 



6. Internal cast of ventral valve. Oriskany formation, New York. 



7. Interior of dorsal valve. 



8. Exterior of ventral valve. 



Oriskany formation, Ridgely member, Cumberland. (Fig. 6 

 after Hall.) 



49 



