PLATE IV. 

 Lima {continned). 



Pias. 



1. L. (riagiostoma) semiornata, d'Orl). Upper Greensand, Ventnor. York 

 Museum. Left valve. Portions of this specimen are enlarged on 



pi. iii, fio-s. l(w/,A. (P. 14.) 



2, 3. L. {Plagio stoma) Meyeri, Woods. Upper Greensand, Warminster. 

 (P. 150 



2. Right valve. useum of Practical Grcology, No. 8839. 



3. Left valve. Sedgwick Museum, Cambridge. 



4 — 6. L. (Plagiostoma) glohosa (Sow). Lower Clialk. 4, -5. Totternhoe 

 Stone, Burwell. G. Zone of HoJ aster snbglohosus, Fulbourn. Sedgwick 

 Museum. (P. 16.) 



4 rt, left valve ; i, dorsal view X 1|; c, portion x 12. 



5 rt, right valve ; b, mid- ventral portion x 12. 



6 a, right valve ; b, dorsal view ; c, median portion x 12. 



7 — 12. L. {Plagiostoma) Hoperi, Mant. (P. 17.) 



7 — 10. Zone of Acfiitocamax quadrat us, East Harnhara. Dr. Blac-kmore's collection 

 7. Left valve ; 8 a, right valve ; 8 b, anterior area of left valve ; 9 a, left valve 

 9 6, dorsal view ; 10, left valve. 



11. Zone of BelemniteUa mucronafa, Norwich. Norwich Museum. 11 a. right 



valve ; \\b, anterior area of the same. 



12. Zone of Micrasfer cor-anguinum, Gravesend. Mr. Diblev's collection. 12 a, left 

 valve ; 12 b, portion x (j. 



13 — 1-j. L. {Plagiostoma) cretacea, Woods. Dr. Blackmore's collection. (P. 22.) 



13, 15. Zone of Actinocamax quadrafus, East Harnham. 13. Right valve x 1^. 

 15. Left valve. 

 14. Upper part of zone of A. qnndratus, Whaddon railway cutting, a, right valve: 

 b, aiitero-dorsal view x lA ; c, portion x (!. 



