INTRODUCTION. XX1 
number of perfect and moveable ribs, by an entire covering 
of scales, which in most families are imbricated, in others 
flat and with their margins in mutual contact. The eyes 
are furnished with eyelids; the ear in some protected by a 
simple valve, in others by scales rather larger than the 
surrounding ones, and in others the tympanum is on a level 
with the surface of the skin. 
In this group are found some of the most active, and 
certainly the most beautiful of the reptile class. Many of 
them are tinctured with the most brilliant colours; and as 
they are called into the greatest activity in the bright sun- 
shine, nothing can surpass the splendour of their ever- 
changing hues. Most of the Saurians are insectivorous ; 
but there are some, as the Iguanas, which live principally 
on fruit. The activity of the smaller insectivorous Lizards, 
when in pursuit of their food, is exceedingly curious and 
interesting. They watch with all the caution of a cat, and 
dart upon their prey with the quickness of lightning. 
In the act of seizing their food, however, they must 
necessarily be exposed to some danger from the noxious 
qualities of the insects which they indiscriminately attack. 
The following fact would seem to indicate that even in our 
own temperate climate, an insect not generally recognized 
as poisonous may inflict a fatal injury upon its Saurian 
enemy :—Some years since, I had in my possession two 
living specimens of the beautiful little green anolis of the 
West Indies, a Lizard about the size of our own smallest 
species. I was in the habit of feeding them with flies and 
other insects, and having one day placed in the cage with 
them a very large garden spider, Hpeira Diadema, one of 
the Lizards darted at it, but seized it only by the leg. 
The spider instantly ran round and round the creature’s 
mouth, weaving a very thick web around both jaws, and 
