THE GEOLOGICAL MIDDLE AGE. 168 
a flying Reptile. But if wo consider its whole 
structure, this does not seem probable, and I be- 
lieve it to have been an essentially aquatic ani- 
mal, moving after the fashion of the Sea-Turtle. 
Its so-called wings resemble in structure the front 
paddles of the Sea-Turtles far more than the 
wings of a Bird ; differing from them, indeed, 
only by the extraordinary length of the inner 
toe, while- the outer ones are comparatively much 
shorter. But, notwithstanding this difference, 
the hand of the Pterodactylus is constructed like 
that of an aquatic swimming marine Reptile ; and 
1 believe, that, if we represent it with its long 
neck stretched upon the water, its large head 
furnished with powerful, well-armed jaws, ready 
to dive after the innumerable smaller animals 
living in the same ocean, we shall have a more 
natural picture of its habits than if we consider 
it as a flying animal, which it is generally sup- 
posed to have been. It has not the powerful 
breast-bone, with the large projecting keel along 
the middle line, such as exists in all the flying 
animals. Its breast-bone, on the contrary, is thin 
and flat, like that of the present Sea-Turtle ; and 
if it moved through the water by the help of its 
long flappers, as the Sea-Turtle does now, it could 
well dispense with that powerful construction of 
the breast-bone so essential to all animals which 
fly through the air. Again, the powerful teeth, 
