LECTURE VII. 
29 
accurately investigated. The common Crocodile 
has been supposed by the ancients to move the 
upper jaw; this the most accurate of the modern 
observers have given up as a mistaken doctrine j 
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 Chamseieons and the Salamanders 
or Water-Newts. The common Chamasleon, 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 j 
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 
