PLATE II. 
CORALS FROM THE CHALK. 
Fie. 
i 
2. 
Various shapes of the corallum of Did/asus Gravensis, Lonsdale. (P. 14.) 
10. 
a 
A, 
6. +The costae, magnified. 
a 
5. The peculiar appearance of tolerably well preserved calices, induced by fossilization, 
magnified. 
8. The method of gemmation, and the appearance of a large calice with the septa 
worn out of it, magnified. 
