CH. l] THE RANGE OF CHAMELEONS. 41 



appear to be often accidentally conveyed on ships, which 

 at' least shows that they have facilities for becoming 

 cosmopolite ; also they have many archaic points in their 

 structure which point to a long existence in the world. 

 The vertebrae are biconcave and have considerable 

 remains of the notochord between the centra; this is a 

 character which occurs in many ancient forms of vertebrates. 

 Though there are not any other families of Lizards which 

 are so widely spread as those which have been just 

 mentioned there are a few others which have a moderately 

 wide range. This may perhaps be partly attributed to 

 the small size as a rule of the lizards and perhaps to their 

 largely insectivorous habits, which renders them more 

 independent of locality, than if they were vegetarian. 

 The fact that many occur upon oceanic islands is a fact 

 which shows that they have greater powers of dispersal 

 than many other groups of animals, and at the same time 

 necessarily renders the study of their distribution less 

 interesting. 



The families Eublepharidse, Iguanidae, Anguidse, Am- 

 phisbaenidae, and Anelytropida? are found in both the Old 

 and the New Worlds. The bulk of the Iguanidae are, 

 however, tropical American, and are very characteristic of 

 the region. The Chameleons have a distribution which is 

 remarkably parallel, as M. Trouessart has pointed out, to 

 that of the Lemurs. The bulk of them are found in 

 Madagascar only, but they also range into Africa and the 

 East Indies. Their arboreal habits, as also in the case of 

 the Lemurs, is perhaps to be compared with their 

 comparatively limited range. A very characteristic Old 



