I have previously alluded to the enormous toads found in South America, and to the gigantic frog which belongs to the northern continent. Among the former I may particularize as one of the largest known species, the _Agua_; and, as remarkable for its mode of gestation, the _Pipa_. The Surinam Toad, or _Pipa Surinamensis_ (the _Bufo Pipa_ of Linné), is distinguished by its large triangular head, and horizontally flattened body, with a granulated back. It is now ascertained that the female deposits her spawn at the brink of some shallow or stagnant pool; the male then collects the heap and cautiously places it on the back of the female, where, after impregnation, they are pressed into cellules produced by the tumefaction of the skin. In rather less than three months the eggs are hatched, and the young emerge in a complete state. The Bull-Frog (_Rana pipilus_), of North America, is from six to eight inches long and from three to four inches broad. When his limbs are fully extended he measures about eighteen inches in length. Its back is of a sombre green colour, varied with black; the under-parts being of a whitish hue, tinged with green, and thickly spotted. The fore-feet have only four toes, and are unwebbed; the hind-feet are large, long, and widely webbed. Its voice may be compared to the distant lowing of a bull, and a chorus of them at night is sufficient to arouse the soundest sleeper. They prey upon ducklings, goslings, and small birds, drowning before devouring them. Spite of its size and ungainliness, it is very nimble, and can accomplish a leap of upwards of six feet in height. [Illustration: 1. Bufo Agua. 2. Pipa Surinamensis.] Incomplete as is this rapid survey of the Fauna of the New World Deserts, I cannot terminate it without referring to the strange and formidable fish which haunt the pools, lakes, and marshes of South America--those _Gymnoti_, or Electrical Eels, sometimes five, six, and even eight feet long, which emit electrical discharges of sufficient violence to strike down a man, a horse, or an ox. It is by this singular property the gymnotus supports its existence; its shocks stupify the smaller fishes and other animals that come within its range, so that they fall an easy prey to its voracity. The electrical organs consist of four bundles of parallel membranaceous laminæ arranged along the inner side of the tail, and constituting a remarkably powerful battery. [Illustration: FISHING FOR GYMNOTI.]