PLATE XIV 



PAGE 



Figs. 1-5. RHIPIDOMELLA LEUCOSIA Hall 166 



1. Interior of dorsal valve. Williams Road, % mile east of Queen City 



Hotel, Cumberland. Romney formation, Hamilton member. 



2. Dorsal valve of specimen of ordinary size. 



3. Ventral valve of the same. 



Hamilton formation, New York. 



4. Interior of dorsal valve showing cardinal process and dental sockets. 



Little Run, near Hancock. 



5. Interior of ventral valve showing muscle scars. Two miles north of 



Hancock. 



Romney formation, Hamilton member. 



Figs. 6-9. RHIPIDOMELLA PENELOPE Hall 167 



6. Broken specimen of ventral valve (?). Evitts Creek. Romney 



formation, Hamilton member. 



7. Interior of dorsal valve. Cumberland. 



8. Enlargement of surface, showing the character of the striae, the 



ordinary puncta and the elongate tubular openings. 



9. Interior of ventral valve showing the muscular impressions and 



cardinal teeth. 



Hamilton formation, New York. 



Fig. 10. RHIPIDOMELLA CYCLAS Hall (?) 169 



10. External impression of ventral valve. X 1%. Williams Road near 



church, S 1 /^ miles southeast of Cumberland. 



Figs. 11, 12. DALMAXELLA LENTICULAKIS (Vanuxem) 164 



11. Dorsal valve (?). X l 1 ^. Ernstville. 



12. External impression of dorsal valve. X l 1 /^. Hanging Rock, 



W. Va. 



Romney formation, Onondaga member. 



Figs. 13, 14. SCHIZOPIIOEIA STBIATULA (Schlotheim) (?) 170 



13. Partly exfoliated ventral valve. Ernstville. 



14. A portion of the lateral margin enlarged, showing punctate 



structure. X 5. 



Romney formation, Hamilton member. 



Figs. 15-17. CAMAROTCECHIA CONGREGATA (Conrad) 171 



15. Interior of dorsal valve. X I 1 /!- 



16. Interior of somewhat distorted small dorsal valve. X I 1 /*. 



17. Partly exfoliated ventral valve. X 1%. Run at eastern end of 



Hancock. 



Romney formation, Hamilton member. 



