126 EXTINCT MONSTERS. 
horn, and the skull in several ways approaches that of a bird. 
Since there are no teeth in the jaws, we may suppose that it 
devoured dragon-flies or other insects, such as we know were in 
existence during the period when the lithographic stone of 
Bavaria was being deposited. ‘Those forms that were provided 
with teeth probably devoured such fishes as they could catch by 
swooping down upon the surface of the water. 
Cuvier thought, from the magnitude of their eyes, that Ptero- 
dactyls were of nocturnal habits. ‘* With flocks of such creatures 
FIG. 34.—Skeleton of Pterodactylus spectabilhs. 
flying in the air, and shoals of no less monstrous Ichthyosauri 
and Plesiosauri swarming in the ocean, and gigantic crocodiles and 
tortoises crawling on the shores of the primeval lakes and rivers 
—air, sea, and land must have been strangely tenanted in these 
early periods of our infant world.” * 
1 Buckland, Sridgewater Treatise. 
