Page:Natural History, Fishes.djvu/299

Rh points of structure and economy, and therefore not without interest to the naturalist, are of little value; their flesh being in general rank and glutinous, and unfit for human food. Most of the species are natives of the tropical seas; though an individual occasionally strays into colder climates. We shall consider them as forming two Families, Tetraodontidæ and Balistidæ.

Instead of teeth arranged in some sort of serried order, the fishes before us have them united into masses, presenting externally no trace of individuality, but internally showing a number of parallel thin plates. The form of these masses of teeth resembles that of a parrot’s beak, and they are covered with a common coat of ivory-like substance. They are continually renewed by the growth of the component plates, as the surfaces are worn down by grinding the sea-weeds and crustaceous animals that constitute the common food of the Family.

Most of the species have the skin covered with prickles, differing in number and strength, and capable of being erected. They are, in general, endowed with the power of inflating the body with air to a remarkable degree. One genus, that of the Sun-fishes (Orthagoriscus), is destitute of both these characters; but it is marked by an equally curious peculiarity of form: the tail being so short, and the posterior termination