OF CREATION. 249 



tionate size, are solid and firmly imbedded in the jaw 

 by a broad and strong bony attachment (fig. 110). 

 The powerful teeth thus inserted were renewed by 

 young teeth, which pressed against, and thus gradually 

 wore away the old ones, and replaced them as they 

 were required. Other teeth of smaller size, but still 

 large, were fitted on the palate, as in the serpents 

 and many fishes. 



The back-bone of the mosasaur was admirably 



Fig. 110 



MOSASAURUS. 



Portion of Lower Jaw. 



adapted for enabling the animal to move rapidly and 

 easily in the water, and the tail seems to have form- 

 ed a powerful vertical oar of large size and great 

 strength. The paddles, too, were of gigantic propor- 

 tions, and in this respect this chalk reptile must have 

 rivalled the Plesiosaurus. All the analogies of the 

 genus, however, seem to have been with the lizard 

 tribe, although involving a perfect application to ma- 

 rine habits, which necessarily introduced considerable 

 modifications of structure. The habits of the mosa- 

 saur were highly predaceous, and it seems to have 

 been the last gigantic form of the marine reptiles 

 before the final destruction of those animals at the 

 close of the secondary period. 



The turtles of the chalk and greensand hardly 



M 5 



