PLATE IV. 



Figure 1. Trochocyathus nummuliticus^ Duncan. The base of tie coral^ natural size. 



2. The hase, magnified, and its ■worn Nummulite. 



3. The calicCj magnified. 



4. Lbptocyathus epithecata, Duncan. The base of the coral, natural size. 



5. The base on a Nummulite, magnified. 



6. The granular septa and pali, magnified. 



7. The costae, magnified. 



8. "Feddenia elongata, Duncan. Side of the coral, rather smaller than nature. 



9. The costse, magnified. 



10. A section of the coral, magnified. 



11. Tkochosmilia Oldhami, Duncan. A large specimen. 



12. The costse, showing the intermediate sets of three, magnified. 



13. Worn-down septa, magnified. 



