Page:Natural History, Reptiles.djvu/247

Rh large masses; they are fertilized externally, in the process of deposition, which always takes place in the water.

The head of these animals is very large, but the cavity of the skull is very small; and yet the brain is scarcely sufficient to fill it. The gape is enormous.

The Anoura are distributed over the whole habitable globe; but they abound most in America, while Africa presents us with very few. These facts are sufficiently explained by the abundance of water in the one continent, and by the scarcity of it in the other. The Order contains four Families, Ranadæ, Hyladæ, Bufonidæ, and Pipadæ.

The Frogs proper are distinguished from the Toads by having small teeth in the upper jaw; most of the species have also teeth in the palate, or rather pointed processes forming a part of the bones to which they are attached, as in the case of certain fishes. From the Tree-frogs they are distinguished by having the toes ending in blunt points, scarcely or not at all dilated, and by terrestrial and aquatic habits. They have always four toes on each anterior foot, and five on the posterior, which are commonly united by a broad swimming membrane, like those of web-footed birds. At the base of the first finger of the hand, there is generally a prominence, more or less obvious, which proves, on dissection, to be the