The whole surface of the body is covered with tubercles, which do not overlap, but are most frequently arranged in transverse series. Some species have the scales of the back set with a ring of small projecting points, the regularity of which is highly ornamental. Those of the lower parts are flat, lengthened, and somewhat six-sided. There is no collar of great scales beneath the neck, but there is a transverse fold of the skin.
The colours of these Lizards vary from black to green more or less deep, with spots which seem to depend on the tubercles, the tints of which, variously grouped, present more or less regular designs, resembling Mosaic work; so that the skin of the Monitors may be employed in the arts like shagreen.
The tongue, unlike that organ in the Families we have described, is fleshy, and very extensile, so that it can be thrown forth to a length double that of the head. The greater part is cylindrical, but the terminal fourth is split into two conical, horny, very flexible points. When retracted, more than half the length is encased in a sort of sheath; and the portion that remains exposed is frequently tinged with bright colours, so as to be easily distinguished by its hue, even when not protruded.
The Monitors are found in both hemispheres; and with the exception of Europe and North America, neither of which have any, the species are equally divided among the great divisions of the globe: viz., four in Africa, four in Asia, four in Australasia, and four in South America.
These are divided into two groups, the ter-
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