LECTURE VII. 29 



accurately investigated. The common Crocodile 

 has heen supposed by the ancients to move the 

 upper jaw: this the most accurate of the modern 

 observers have given up as a mistaken doctrine ; 

 but a naturalist of the French school, Monsieur 

 Geoffroy, has lately revived- the ancient doctrine, 

 and contends that this circumstance really takes 

 place in the Nilotic Crocodile. 



As farther examples of the Lizard tribe I shall 

 only mention the Chameleons and the Salamanders 

 or Water-Newts, The common Chamagleon, a 

 native of many of the warmer parts of the world, 

 and particularly of Africa, has long been cele- 

 brated for its supposed power of changing its co^ 

 lour at pleasure according to the object on which 

 it is placed. This is a vulgar error ; but it is true 

 that the animal does every now and then change 

 its colour in a surprising manner, from some par- 

 ticular causes not well understood. The general 

 colour of the animal is a greyish or blueish green - y 

 and this often becomes, in the space of a few mo- 

 ments, variegated with spots and patches of red, 

 brown, yellow, and other shades. The size of the 

 full-grown Chamseleon is sometimes nearly a foot, 

 exclusive of the tail; which is at least of equal 



