452 MANUAL OF ZOOLOGY sect. 



The lizards are for the most part terrestrial animals, 

 usually extremely active in their movements and endowed 

 with keen senses. The majority readily ascend trees, and 

 many kinds are habitually arboreal ; but the chamaeleons 

 are the only members of the group which have special modi- 

 fications of their structure in adaptation with an arboreal 

 mode of life. The skinks and the amphisbsenians are 

 swift and skilful burrowers. The geckos are enabled by the 

 aid of the sucker-like discs on the ends of their toes to run 

 readily over vertical or overhanging smooth surfaces. A 

 few lizards, on the other hand, live habitually in fresh water. 

 The flying lizards {Draco) are arboreal, and make use of 

 their wings — or, to speak more accurately, aeroplane or para- 

 chute (thin folds of skin supported by the greatly produced 

 ribs) — to enable them to take short flights from branch to 

 branch. Chalmydosaurus and certain other genera are 

 exceptional in frequently running on the hind-feet, with the 

 fore-feet entirely elevated from the ground. A tolerably 

 high temperature is essential for the maintenance of the 

 vital activities of lizards, low temperatures bringing on an 

 inert condition, which usually passes, during the coldest 

 part of the year, into a state of suspended animation or 

 hibernation. The food of lizards is entirely of an animal 

 nature. The smaller kinds prey on insects of all kinds, and 

 on worms. Chamaeleons, also, feed on insects, which they 

 capture by darting out the extensile tongue covered with a 

 viscid secretion. Other lizards supplement their insect diet, 

 when opportunity offers, with small reptiles of various kinds, 

 frogs and newts, small birds and their eggs, and small mam- 

 mals, such as mice and the like. The larger kinds, such as 

 the monitors and iguanas prey exclusively on other ver- 

 tebrates ; some, on occasion, are carrion-feeders. Most 

 lizards lay eggs enclosed in a tough calcified shell. These 



