PLATE XVIII. 



Strophomena rhomboidalis. 

 Fig. 1-3. Ventral, dorsal and profile view of a specimen. Page 150 



Strophodonta hemispherica. 



Fig. 4-6. Ventral, dorsal and lateral view of specimen. Page 144 



Fig. 7-9. Dorsal, ventral and lateral view of an internal cast. 



Strophodonta demissa. 



Fig. 10-15. A series of specimen showing variations in size. Page 143 



Fig. 16. Lateral view of a specimen. 



Strophodonta perplana. 



Fig. 17. Ventral view of a specimen. Page 147 



Ghonetes acutiradiata. 



Fig. 18-20. Ventral, dorsal and profile view of a specimen. Page 66 



