PLATE IV. 



CORALS FROM THE CHALK. 



Fig. 



1. The corallum of Trochosmilia {Calosmilid) graiiulala, Duncan. (P. 10.) 



2. The costse, magnified. 



3. The cellular margin, magnified. 



4. The peduncle, magnified. 



5. The corallum of Trochosmilia {Ccehsmilia) Woodwardi, Duncan. (P. 9.) 



6. The costaj, magnified. 



7. The septa, magnified. 



8. The peduncle, magnified. 



9.1 The corallum (nat. size and enlarged) of a variety of Trochosmilia {Coelosmilia) lasca, 



10. J Ed. and H. (P. 8.) 



11. The costae, magnified. 



12. The calico, magnified, showing the septa of the fourth cycle. 



