PLATE VIII. 



Genus — Pteria, Scopoli. 

 Sub-Genus — Oxytoma, Meek. 



Figs. 



1 — 7. P. {Oxytoma) Comueliana (d'Orb.). 1—6. Speeton Series (D, 1), 

 Speeton. 7. Claxby Ironstone, Claxby. (P. 57.) 



1. Sedgwick Museum. Left valve. 



2. York Museum. Left valve. 



3. Sedgwick Museum, a, left valve; o, postero-ventral portion x 3. 



4. Mr. Lamplugh's Collection. Left valve, portion near ventral margin x 3. 



5. Mr. Lamplugh's Collection. Eight valve. 



6. York Museum. Eight valve. 



7. Sedgwick Museum. Eight valve. 



8—14. P. {Oxytoma) pectinate (Sow.). (P. 59.) 



8 — 10. Folkestone Beds, Folkestone. Sedgwick Museum. Left valves, 8 a, x 1| ; 



8 b, portion of 8a x 6. 10 a, X 2 ; 10 b, portion of 10 a x 8. 

 11, 12. Hythe Beds (Bargate Stone), Busbridge. Sedgwick Museum. Eight valves. 



x 1*. 

 13, 14. Gault, Folkestone. British Museum, No. L, 4926. 13, left valve. 14 a, right 



valve ; 14 b, portion of 14 a x 8. 



15. P. {Oxytoma) sp. Totternlioe Stone, Hitchin. Left valve. Museum of 



Practical Geology, No. 2338. 15 a X 3 ; 15 6, portion X 9. (P. 60.) 



16. P. {Oxytoma) dubia (Etli.). Totternlioe Stone, B unveil. Sedgwick 



Museum. One of the Types. Exterior {a) and interior {(>) of right 

 valve. X 2. (P. 60.) 



17—23. P. {Oxytoma) tenuicostata (Romer). Upper Chalk. (P. 61.) 



17,18. A. quadratus zone, West Harnham. Dr. Blackmore's Collection. 17 a, left 

 valve ; b, portion near mid-ventral margin X 4 ; c, interior ; d, hinge X 3. 

 18, left valve x 2. 



19,20. Coddenham. Museum of Practical Geology, Nos. 10788, 12620. 19 a, left 

 valve; b, portion near the mid-ventral margin x 6. 20 a, left valve ; b, pos- 

 terior ear x 2. 

 21—23. Wells. Norwich Museum. Nos. 3249, 3250, 3251. 21 a, left valve ; 21 b, portion 

 near mid-ventral margin x 3. 22, left valve. 23, right valve and interior of 

 the marginal part of the left valve. 



