PLATE XXVI. 



Plicatula (continued). 



Fias. 



1 — 11. P. inflata, Soav. AVooclwardian Museum, Cambridge. Right valves 

 (except fig. 7). (P. 139.) 



1 — 3, 5. Totternlioe Stone, Burwell. 

 4. Lower Chalk, Burwell. 



6. Totternlioe Stone, Arlesey. 



7. ,, ,, Eeacli. Left valve. 



8. „ „ Burwell. 



9. Lower Chalk, Burwell. 



10. Chalk Marl, Haslingfield. 



11. H. suhglohosns zone. Cherry Hinton. 



12 — 18. P. Barroisi, Peron. Right valves, except figs. 13, 14. (P. 141.) 



12. H. planus zone, Dover. Dr. Eowe's Collection, a, natural size ; t, x 4. 



13. IT. ^J?fm2<s zone, Twyfoi'd. Woodwardian Museum. Left valve, o, natural 



size ; &, X 4. 



14. To2> of M. cor-anguinum zone, North Foreland. Dr. Rowe's Collection. 



Left valve, a, natural size ; h ,x 4. 



15. H. planus zone, Dover. Dr. Rowe's Collection, a, natural size ; 6, x 4. 



16. t7mtom»izts-band, Kingsgate, Margate. Dr. Rowe's Collection. «, natural 



size; h, x 4. 



17. H. planus zone, Twyford. AVoodwardian Museum, a, natural size ; h, x 4. 



18. Chalk Rock, near Winchester. Mr. R. M. Brydone's Collection, a, natui-al 



size ; 6, X 4. 



19—22. P. sigillina, Woodw. (P. 143.) 



19. B. mucronata zone, Hartford Bridge, Norwich. Woodwardian Museum. 



ft, interior of right valve ; h, central part of same x 2. 



20. Top of M. cor-testudinarium zone, Chatham. Dr. Rowe's Collection. 



Left valve. 



21. Same horizon, etc. Left valve x 2. 



22. M. cor-testudinarium zone, Chatham. Museum of Practical Geology, 



No. 179. Left valve. «, natural size; h, x 2. 



