PLATE II. 



Paracyclas elliptica. 



Fig. 1-3. Right, left and cardinal view of specimen. Page 209 



Paracyclas lirata. 



Fig. 4. Left view of a specimen. Page 211 



Fig. 5-7. Left, right and cardinal view of specimen. 



Paracyclas elongata. 



Fig. 8. Left view of a specimen. Page 210 



Modiomorpha concentrica. 



Fig. 9, 10, 14. Left view of specimen, showing variations in size and 



ornamentation. Page 219 



Fig. 11. 12. Right and profile view of specimen. 



Crania bordeni. 



Fig. 14. View of two specimens adhering to left valve of Modiomorpha 



concentrica. Page 32 



Ptychodesma knappianum. 



Fig. 13. Profile view of a specimen. Page 201 



Fig. 15. Left view of a specimen. 



Fig. 16. Left view of a smaller individual. 



Fig. 17. Right view of a specimen, showing striated ligamental area. 



Fig. 18. View of left valve enlarged, showing striated ligamental area. 



