Page:Natural History, Reptiles.djvu/256

248 is provided with suckers, analogous to those we have noticed in the foot of the Gecko.” Each toe, both of the fore and hind feet, is dilated at the tip into a circular pallette or pad, varying in size in different genera: these little cushions are, it is true, moistened with a glutinous fluid, as is the whole surface of the body; but we believe that this viscidity is not, as has been supposed, the agent by which the animal so powerfully adheres against gravity; but that the pallettes act as suckers, being sustained in their position by the pressure of the atmosphere, a vacuum being produced beneath them, or removed at the creature’s will.

The colours of the Tree-frogs are various, and are often brilliant and beautiful; like many other Reptiles they have the faculty of changing their hues to an extent that often affords them protection, by rendering them difficult to be discerned. They are very numerous in the damp woods of tropical America, residing habitually by day in the concealment afforded by the huge Bromeliaceæ or Wildpines, and other parasitical plants that grow in tufts on the trunks and branches of great trees, the sheathing bases of whose leaves not only afford them umbrageous bowers in which to dwell, but also form reservoirs in which the rain-water collects, and thus provide the moisture without which they would soon expire. The under-surface of the bodies of these arboreal Frogs is very different from that of the terrestrial species; the skin, instead of being smooth, is covered with granular glands pierced by numerous pores, through which the