REPTILTA. 270 



ribs do not support the membrane — the animal is enabled to glide in safety 

 for a considerable distance through the air. The best known species is D. 

 dandini, or flying dragon of Java (/>/. 81, fig. 33, and pi 89, fig. 3). The 

 genus Agama {pi. 74, fig. 77) Avas formerly made to include the North 

 American Tropidolepls and Phrynosoma. As restricted it now includes 

 no American species. StelUo {pi. 74, fig. 78) contains the only European re- 

 presentatives of the IguanidcB, *S'. vulgaris. 



Fatn. 5. ChamcBleontidm (the chamoeleons). This family, containing but 

 a single genus, Chamadeo, with 14 or 15 species, is separated by the most 

 strikinMv marked characters from all the other divisions of the Saurian 

 order. The first peculiarity of the chamfeleons consists in the absence of 

 scales. The skin, however, unlike that of the Bati'achia, is dry, and 

 supplied with fine granulations of unequal size but of symmetrical distri- 

 bution. The body is much compressed, so much so that the back and 

 belly, in some cases, appear provided with crests. The feet, longer in 

 proportion than those of any other saurian, are provided with five toes 

 each, arranged in two sets, one including two and the other three. In the 

 fore feet, the binary packet is exterior, the opposite being the case in the 

 posterior extremities. In fact, the toes are all united together as far as the 

 claws by the skin, and this then appears divided betAveen the second and 

 third, or between the third and fourth toes. The head is large, and, owing 

 to the shortness of the neck, appears to rest on the shoulders. The orbits 

 are very large, and the eyes are covered by a single annular pupil, with a 

 dilatable central aperture. Either eye can be moved separately, and the 

 two may be looking in entirely opposite directions at the same time. 

 There is no external meatus auditorius. The mouth opens beyond the 

 eyes, and is provided with trilobed cutting teeth, arranged in a single series 

 along the sharp edges of the two jaws. A highly curious feature is to be 

 found in the tongue, which, when at rest, appears like a fleshy tubercle, 

 capable, however, of being suddenly protruded to a distance equal to the 

 length of the body. The tip of the tongue is covered with a sticky secre- 

 tion, by means of which small insects are secured. The tail is prehensile, 

 and like that of the American monkeys can be used as an instrument of 

 progression. The chamajleons are especially arboreal, a condition of life 

 for which they are well fitted by reason of the opposable divisions of the 

 feet and the prehensile tail. Tlieir motions are exceedingly slow, and 

 when stealing on their prey (minute insects) almost imperceptible. When 

 arrived within a proper distance of the object of tlieir pursuit, the tongue 

 is protruded with inconceivable velocity, and retracted almost as quickly. 

 The changes of color experienced by the skin of the chamfeleon have made 

 it an object of curiosity from the most remote time. Highly exaggerated 

 notices of this phenomenon are to be found in the writings of many of the 

 ancients ; more recent investigations, however, have dispelled much of the 

 fable attaching to this curious animal. A change of color, under diiferent 

 circumstances, is not peculiar to the chamaeleon, but is exhibited by many 

 of the tree-frogs, and in fixct by most of the anourous batrachia. In all, it 

 appears to depend, in some obscure way, upon the loose attachment of the 



483 



