HABITS. 109 



Tropical India as regards its Amphibians, while Australia and Africa are near 



akin to South America in regard to their tortoises, in respect of lizards there is no 



close connection between India and Africa, but an intimate relationship exists 



between India and Australia, where members of the same genera occur ; while the 



Australian lizards are totally unlike their South American cousins. As might have 



been expected from their great numerical preponderance at the present day, lizards 



appear to be a comparatively modern group, their remains being rare in the lower 



Tertiary deposits, while in the Secondary period they are only known by a few 



species from the rocks of the Cretaceous epoch. That the group has originated 



from the tuateras, which were so abundant in the earlier strata of the Secondary 



period, may be regarded as most probable. 



Turning to their mode of life, we find that while a few members 

 Habits. „ 



of the order resemble crocodiles, in spending the greater portion of 



their time in water, visiting the land only for the purposes of feeding, sleeping, 

 or basking in the sun, by far the great majority of lizards are essentially land- 

 animals, avoiding even damp situations. Although some inhabit trees, the greater 

 number dwell either on the ground or among the clefts of rocks ; the conformation 

 of the body generally giving some indication of this diversity of habitat. Among 

 the land forms, for instance, those with depressed bodies are generally to be found 

 in open sandy deserts, where they seek shelter either beneath stones or in holes ; 

 whereas such as have the body compressed are more usually dwellers among 

 bushes or in trees. Those, again, in which the body is more or less cylindrical, are 

 in the habit of secreting themselves in the clefts of rocks or the chinks of tree- 

 stems; while the snake-like kinds live on the ground, and those with a more 

 worm-like form beneath its surface. The movements of the greater number of 

 species — whether they live on the ground, among rocks, on trees, or on cliffs or 

 walls — are agile in the extreme; and while the majority run with their bodies 

 close to the ground, many habitually raise themselves up at times by resting on 

 their hind-legs and tails, and are able to spring, either on the ground or from 

 branch to branch, to a considerable distance after their prey. Of the arboreal 

 species, some make use of their tails to aid in maintaining their hold, while others, 

 together with cliff- and wall-hunting species, like the geckos, are enabled to run 

 along the under sides of boughs, or to ascend vertical surfaces by the aid of their 

 expanded and disc-like feet. The peculiar flying lizard is enabled to take long, 

 flying leaps, supported by a parachute-like membrane borne by the expanded ribs ; 

 while all the limbless species move somewhat after the manner of snakes, although 

 making less use of the extremities of the ribs. The few aquatic forms swim and 

 dive without the aid of webbed feet ; but many other kinds swim well if 

 thrown into water. 



In many cases elegant and graceful in form, although at others rendered more 

 curious than beautiful by the presence of spines or warts, lizards are pleasing 

 rather than repulsive animals ; and, with the exception of the American heloderms, 

 none are poisonous, although some will bite sharply. Few lizards possess a distinct 

 voice, the majority merely uttering a low hiss ; some, however, especially among 

 those whose habits are nocturnal — emit a clear, sharp cry, which has been likened 

 both to the scream of a frog, and to the chirp of a cricket. Of their senses, the 



