TAB. IV. 



Fig. 

 1 — 10, 13 — 16. Teeth of Ichthyosaurus campylodon. 



From the Chalk and Green-sand of Cambridgeshire. In the Collection of 

 James Carter, Esq., of Cambridge. 



1 1 . Back tooth of a recent Alligator, showing the circular hole made by the ab- 



sorption consequent on the pressure of a young tooth. 



12. Tooth of a recent Crocodile, showing the young tooth, that has penetrated the 



pulp-cavity of the old tooth. 



17. Tooth of Ichthyosaurus communis, from the Lias of Lyme Regis. 



All the figures are of the natural size. 



