298 VERTEBRATES : REPTILES. 



on air. They live upon trees, are excessively slow in 

 their movements, and often remain motionless upon a 

 branch for hours. The great size of their lungs is 

 probably the source of the power of the Chameleons to 

 change their color, which takes place according to their 

 feelings, and not in conformity with the hues of the bodies 

 on which they rest, or near which they pass. The very 

 extensible tongue has the extremity covered with a viscid 

 secretion ; and when the animal has marked an insect, it 

 darts forth this organ, and quicker than a glance of the 

 eye secures the prize for food. Eight or ten species or 

 more inhabit the warmer parts of the Old World. 



SCINCOID^E, OR SKINK FAMILY. This Family com- 

 prises lizards which have the bocly cylindrical, and cov- 

 ered with smooth scales, variable in form and size, and 

 disposed in the form of a quincunx. The head is covered 

 with large, thin, angular plates ; the neck is of the same 

 size as the thorax ; tongue free, flat, and notched, and 

 not retractile into a sheath ; and the jaws are furnished 

 with closely set teeth. The body and tail seem to be one 

 continued and uniform piece. The genera and species 

 are quite numerous. 



The Genus Plestiodon has the head very large and 

 broad behind, but contracted in front of the eyes. 



The Scorpion, or Red-headed Skink, P. erythrocephahis, 

 Holbrook, of the Southern Atlantic and Gulf States, is 

 twelve or thirteen inches long, olive brown above, the 

 throat and abdomen yellowish white, and the head above 

 bright red. It lives in hollow trees, and seldom comes to 

 the ground except for food and water. It is generally 

 timid, but when captured is very fierce, and bites severely ; 

 but its bite is not venomous, as is generally believed. 



The Genus Scincus contains the Five-lined Skink, 

 5. quinquelineatus, Daud., of the Southern States, which 

 is about ten inches long, the head pale red, with six ob- 



