Page:Natural History, Fishes.djvu/15



Class of Fishes possesses a greater number of known species than any other of the primary divisions of Vertebrate animals; perhaps, indeed, when we consider the ratio which water bears to land on the surface of our globe, and the peculiar difficulties which attend the study of these animals, it may not be extravagant to suppose that the species of Fishes exceed in number those of Mammalia, Birds, and Reptiles put together. The number of individuals, also, composing the different species, in general, much exceeds the average as found in the other Classes, arising as well from the extent and depth of the element which they inhabit, as from their astonishing fecundity. The eggs of a bird are reckoned numerous when they amount to a score, but the eggs of fishes are commonly counted by thousands, and in some cases even by millions! In the ovary of a Cod, nine million eggs have been ascertained to exist, and Mr. Jesse asserts that "the ovary of one female Salmon will produce twenty million eggs." When we add that fishes yield an immense quantity of agreeable