Page:Natural History, Reptiles.djvu/80

72 One of the most remarkable features in the physiognomy of the Chameleons is the peculiarity of their eyes; these are large, full, and prominent, entirely covered with the common shagreened integument, except a small round aperture opposite to the pupil. Unlike all other vertebrate animals, their eyes act independently of each other, so that one may be directed to an object before, while the other remains still, or is looking behind.

The head in the Chameleons is large, somewhat triangular in outline, and appears set upon the shoulders without the intervention of a neck; it is very broad across the occiput, where it is surmounted by an elevated process, greatly developed in some of the species; ridges also proceed over the eyes, which meet at the muzzle, and are sometimes much prolonged.

The Chameleons, though constituting but a single genus, comprise numerous species, which are scattered over the warmer regions of the eastern hemisphere, from the south of Spain, and the countries bordering the Mediterranean, to Australia. No species is known to exist in America, where the genus seems to be replaced by Anolis and its allies.