412 



REPTILIA— ORDER III.—SQUAMATA. 



wide, -while, owing to the great relative length of the lanky limbs, it is raised 

 high above the ground. The long tapering tail is as good a grasping organ as 

 that of an American monkey. Externally, the whole surface is covered with 

 granules, or small tubercles, so that, properly speaking, chamseleons do not come 

 under the title of Squamata. In their skeleton, chamasleons differ from all 

 lizards with fully-developed limbs by the complete loss of their collar-bones. 

 Chamseleons are all so closely related to one another that a single family — 

 the Ghamcdeontidoi — suffices for the group. Moreover, with the exception of 

 three Malagasy species forming the genus Brookma, 

 and two others from Africa, which are separated 

 as Bainpholeon, all the forms may be included in the 

 typical genus Chainceleon, of which forty-four specific 

 representatives are recognised. As regards their 

 geographical distribution, chamseleons are chiefly 

 characteristic of Africa south of the Sahara and Mada- 

 gascar ; but the common Chamcdeon vulgaris is an 

 inhabitant of many of the Eastern Mediterranean 

 countries, and is also found in Andalusia and Algeria. 

 India and Ceylon likewise possess a representative of 

 the same genus, while South Arabia is the home of a 

 third, and Socotra of a fourth. Great difference 

 exists in the bodily size of the various members of the 

 family ; the smallest being a species of Brookesia 

 measuring less than three inches in length, while 

 many of the larger kinds grow to considerably more 

 than a foot. 



ChamEeleons are essentially arboreal animals, mostly living in trees or 

 bushes abundantly clothed with leaves, and in localities where moisture is 

 plentiful. Although these reptiles have long been celebrated for their power 

 of changing the colour of their skins, yet it appears that the phenomenon is 

 by no means so strongly marked in this group as it is among certain lizards. 

 Still there is considerable change ; and whereas most chamseleons are gener- 

 ally of an apple-gi-ecn colour in daylight, it is stated that during the night the 

 tint of the skin fades to a greyish-white. If during the daytime a chamseleon 

 passes Trom a leaf to a bough, its skin soon assimilates to the sombre hue 

 of the latter ; and if seized in the hand the change is even more rapid. In spite 

 of the partiality of nearly all the species for dense tropical or sub- tropical vegeta- 

 tion, a few have betaken themselves to spots in desert districts where they find 

 herbage enough for their needs. All are insectivorous, their favourite food 

 being flies ; and the rapidity with which one of these insects is seized by the 

 tongue forms a strange contrast to the otherwise sluggish and deliberate move- 

 ments of these reptiles. 



Fi(f. 21. — A Chameleon. 



Suh-Onhr Ill.—Oph idia. 

 Snakes. 



The loading structural features by which snakes are distinguished from the 

 limbless lizards having been already given under the heading of the sub-order 

 Lacertilia, these need not be recapitulated, and attention may accordingly be 

 directed to some of the other characteristics of the former group. Everybody 

 is aware that snakes are scaly reptiles, crawling on the ground without the 



