204 EXTINCT MONSTERS 
Cuvier thought, from the magnitude of their eyes, that Ptero- 
dactyls were of nocturnal habits. ‘ With flocks of such creatures 
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 
Fic. 74.—Skeleton of Pterodactylus spectabilis. 
—air, sea, and land must have been strangely tenanted in these 
early periods of our infant world.” ? 
It was thought at one time that Birds differed from Pterodactyls 
in the absence of teeth; but this only holds good for modern 
birds. If we go back to the Mesozoic age, we find that birds 
at that time did possess teeth. The oldest known bird, the 
Archeopteryx, had teeth in its jaws, and presents some very 
striking points of resemblance to reptiles (see p. 215). But if 
1 Buckland, Bridgewater Treatise. 
