348 THE BOOK OF THE ANIMAL KINGDOM 



food and have gradually developed their limbs in adaptation to their 



surroundings. In the course of time the wing-like membrane would 



become more and more extensive, until a creature originally of the 



land became a beast of the air. But such a development would 



involve the activity of the law of natural selection through very 



many generations. Certain it is that winged reptiles were actually 



in existence "once upon a time." They had not the wings of a 



bird, but a loose thin membrane such as our modern Bats possess. 



Many of the Pterodactyles were quite small, perhaps not so large as 



the Common Bat, but some species attained great size, their flying 



apparatus extending between twenty and thirty feet. Their remains 



indicate big heads, strong, toothed jaws, large eyes, giving good 



vision, and the power to perch on trees and hang on cliffs. These 



reptiles must have fulfilled the role of the fiend as given in the 



lines — 



" The fiend 

 O'er bog or steep, through strait, rough, dense, or rare, 

 With head, hands, wings, or feet, pursues his way. 

 And sinks, or swims, or wades, or creeps, or flies." 



They could fly with ease, stand erect upon tlje ground and crawl 

 by the aid of their four limbs, the wings being neatly tucked up for 

 the occasion. It is not unlikely that they sometimes swooped upon 

 fish as they rose in the water, and they may also have consumed 

 the insects common in their time. Perhaps it was these creatures, 

 aptly termed the "Flying Dragons," that in some way yet to be 

 explained gave rise to the idea of the mythical dragons of the fables. 

 SEIXOSAURS. — The Deinosaurs (Greek, deinos, terrible; sauros, 

 reptile) appeared in Triassic time, but reached a greateJr state of 

 development in the Jurassic period. These were the greatest of 

 Land Reptiles. One of their number, the Megalosaurus (large 

 repdle) is figured on Plate VIII. It is correctly represented as a 

 carnivorous beast, for its teeth were like those of a Tiger. Doubt- 

 less it had no compunction in killing and eating its herbivorous 

 cousins. It will be noticed that it had a Kangaroo-like build. It 

 walked mainly upon its massive hind-legs, although it may some- 

 times have gone on all-fours. Its fore-legs were used for grasping 

 prey. It would occupy shallow waters on occasion, but would 

 generally move along the margins of lakes and marshes in search 

 of food. The appearance of this creature could not have been 

 particularly inviting, but it was not so huge as some of its relatives. 



