210 EXTINCT MONSTERS 



Probably the large Pterodactyls of the Cretaceous period, 

 soaring like albatrosses and giant petrels over the surface of the 

 ocean, co-operated with the marine reptiles, such as Ichthyosaurs, 

 Plesiosaurs, crocodiles, and others, as those sea-birds now do with 

 the whales, porpoises, and dolphins, in reducing the excessive 

 numbers of the teeming tribes of fishes, and in maintaining the 

 balance of oceanic life. 



With regard to the place of Pterodactyls in the animal kingdom, 

 Professor Seeley placed them as a distinct sub-class, side by side 

 with birds, and between mammals and reptiles, thus 



Mammalia. 



g 



o 



Reptilia. 



The name Ornithosauria (bird-lizards) is frequently used instead 

 of the other name, because it expresses the idea of their being 

 partly saurian and partly bird-like. 



They flourished from the period of the Lias to that of the 

 Chalk ; and then, like so many other strange forms, seem to have 

 suddenly disappeared. 



