26 
LECTURE VII. 
arrived at its state of perfection, appears less than 
the Tadpole from which it was gradually formed. 
Nor is this peculiar to the Surinam Frog or Rana 
paradoxa, but takes place in some of the Euro- 
pean animals of this genus, which are rather larger 
in the tadpole state than when first arrived at their 
perfect form, as in the species called the R. al~ 
liacea or alliaceous Toad, a native of Germany, 
and some other parts of Europe. 
To the Frogs succeed the Lizard tribe, con- 
stituting the Linnjean genus Lacerta, and dis- 
tinguished by having a lengthened body, four 
feet, and a tail. The Lizard tribe is extremely 
numerous, and contains many animals of vast 
size, as the Crocodiles and Alligators ; and others 
very small, as the common Newts. For the con- 
venience of zoological students the genus may be 
divided into assortments arranged according to 
the habit or general appearance of the species. 
First the Crocodiles, distinguished b}^ very large 
and strong scales. The Guanas, commonly fur* 
nished with a serrated process along the back, 
and often by a pouch or flap under the throat. 
The Cordyles, with serrated or toothed scales. 
The Lizards emphatically so called, with smooth 
