PLATE XXXIV. 



Gykopleuba {continued). 



Figs. 



1. (I. sp. Upper Chalk (zone of Actinocamax plenus), Seaford. Mr. F. R. B. 

 Williams' Collection, a, left valve and umbonal part of right valve; 

 b, posterior vieAV of both valves ; c, ornamentation of left valve X 3 ; 

 d, ornamentation of right valve X 3. (P. 210.) 



Genus — Corbula , Brug mere. 



2 — 5. G. angulata (Phill.). Speeton Clay, Speeton. 2, 5, Sedgwick Museum ; 

 3, 4, Mr. Lamplugh's Collection. (P. 210.) 



2 a, left valve ; b, dorsal view of both valves ; c, anterior view, x 5. 

 3, 4. Left valves x 5. 

 5. Eight valve x 5. 



6 — 12. C. striatula, Sow. Lower Greensand (Atherfield Beds), East Shalford ; 

 except 7 and 12, from the Crackers, Atherfield. Sedgwick Museum. 

 X 5. (P. 212.) 



6 — 10. Right valves. 9 b, dorsal view of 9 a. 



11 a, left valve ; b, dorsal view of both valves. 

 12. Anterior view of both valves. 



13. G. sp. Lower Greensand, Punfield. Museum of Practical Geology, 

 No. 22723. Right valve, the posterior part broken, X 5. (P. 213.) 



14—16. G. gauLtina, Pict, and Camp. Gault, Folkestone, x 5. (P. 214.) 



14. Sedgwick Museum, a, right valve; b, dorsal view of both valves; c, anterior 

 view. 

 15, 16. Museum of Practical Geology, Nos. 22727, 22728. Left valves. 



17 — 22. (J. truncata, Sow. Upper Greensand, Blackdown. Sedgwick Museum. 

 X 5. (P. 215.) 



17—19. Eight valves. 

 20, 21. Left valves. 20 b, dorsal view of 20 a. 



22a, posterior view of left valve x 5; b, ornamentation near the middle of the 

 ventral margin x 10. 



23 — 28. G. elego ns, Sow. Upper Greensand, Blackdown. Sedgwick Museum. 

 X 5. (P. 210.) 



23—26. Right valves. 



27. Anterior view of both valves. 



28 a, left valve and umbo of right valve ; b, dorsal view of a. 



