PLATE 10 



Fig. i. Oligosphaeridiutn vasijormum (Neale & Sarjeant). Holotype, V.5i709(3). 

 Two precingular processes missing. x 400. 



Fig. 2. Hystrichosphaeridium tubiferum (Ehrenberg). London Clay ; (5 feet above 

 base of London Clay) Sheppey. Sh. 1/2(1). X425. 



Fig. 3. Oligosphaeridiutn complex (White). London Clay ; (146 feet above base of 

 London Clay) Whitecliff Bay. Apical archaeopyle (sutural notch to the west) surrounded by 

 6 precingular processes. WC. 16/1(1). X425. 



Fig. 4. Hystrichosphaeridium costatum sp. nov. Holotype, V. 5 1708. X500. 



Fig. 5. Hystrichosphaeridium patulum sp. nov. Holotype, ¥.51739(1). X1250. 



Fig. 6. Hystrichosphaeridium salpingophorum (Defiandre). ¥.51734(1). X500. 



Fig. 7. Cleistosphaeridium diversispinosum gen. et sp. nov. Holotype, ¥.51750(1). 

 X400. 



Fig. 8. Hystrichosphaeridium latirictum sp. nov. Holotype, ¥.51740(1). X975. 



Fig. 9. Oligosphaeridium pulcherrimum (Defiandre & Cookson). London Clay 

 (78 feet above base of London Clay) ; Sheppey. Positions of the processes well shown, the 

 absence of cingular processes being noticeable. Sh. 2/5(1). X875. 



Fig. 10. Hystrichosphaeridium tubiferumvar. brevispina nov. Holotype, ¥.51738(1). 

 X500. 



