TAB. II. 



Fig. 3. 



Cythere umbonata. 



« X 50 



^ X 50 



c X 50 



d X 



g X 



e X 100 



/ X 50 



y X 50 



^0 

 50 



Perfect, dorsal aspect . 



Perfect, ventral aspect 



Young, perfect, ventral aspect 



Perfect, posterior aspect 



Perfect, placed obliquely, left valve upwards 



Punctations (of fig. 3 e) 



Right valve, outside 



Left valve, inside 



Detritus. Charing. 



Fig. 4. Cythere Faba. 



« X 50 Perfect, right valve upwards 

 ^ X 50 Perfect, dorsal aspect 

 c X 50 Perfect, anterior aspect 



Fig. 5. Cythere Bairdiana. 



Right valve, inside 

 Right valve, dorsal edge 

 Right valve, anterior aspect 



Fig. 6. Cythereis interrwpta. 



Left valve, outside 

 Perfect, dorsal aspect . 

 Punctations 



Var. a, left valve, outside 

 Var. a, perfect, ventral aspect 

 Var. j3, left valve, outside 

 Var. |3, right valve, inside 

 Var. /3, perfect, anterior aspect 



Fig. 7. Cythereis Galtina. 



Right valve, outside 

 Left valve, inside 

 Left valve, dorsal edge 



Fig. 8. Cythereis macrophthalma 



Left valve, outside 

 Left valve, inside 

 Left valve, dorsal edge 

 Right valve, outside 

 Right valve, inside 

 Right valve, dorsal edge 

 h"'Y, 50 Right valve^ anterior edge 



a X 



50 



b X 



50 



c X 



50 



a X 



50 



e X 



50 



h xlOO 



h X 



50 



/x 



50 



c X 



50 



d X 



50 



9 X 



50 



a X 



50 



b X 



50 



c X 



50 



a X 



50 



a X 



50 



ay. 



50 



b X 



50 



b'y 



50 



b"X 



50 



Detritus. Charing. 



Greensand. Farringdon. 



Detritus. Charing. 



Gault. Lea con HiE. 





Folkstone. 



Gault. 



Folkstone. 



Chalk. 



Norwich. 



