PLATE 37. 



Page 



Figs. 1-4. Spiripbra granulifera var. clintoni -I'l'-i 



1. Dorsal view of a small individual. 



2. Ventral view of the same. 



3. Profile of the same. 



4. Ventral view of a much larger specimen. 



Fig. 9. Spirifera medialis ? 227 



9. Dorsal view of a young specimen, doubtfully referred to this species. 



Figs. 10 - 20. Spirifera marcyi 220 



10. Dorsal view of a small individual of this species. 



11. Ventral view of the same. 



12. Ci^rdinal view of the same. 



13. Dorsal view of an unsymmetrical specimen of gibbous form, showing the area and foramen. 



14. View of a ventral valve of another individual. 



15. Ventral view of a more extended form. The front of tha shell is shortened by crashing. 



16. Profile view of specimen fig. 13, showing the great rotundity of the dorsal valve. 



17. Interior of a dorsal valve, showing the cardinal process and dental sockets. 



18. Enlargement of surface, showing the elongated pustulose markings characteristic of (liis 



species. 



19. Cardinal view of an mdividual, which is imparfeot at the extremities. The valves are less 



gibbous than in fig. 16. 



20. Interior of an imperfect ventral valve, showing the broad muscular impression. 



