Sturgeon (Acipenseridæ) deposits enormous numbers of extremely minute eggs, the product of a single individual having been estimated at upwards of three millions during a season. This fecundity is necessary to preserve the species, when, apart from other enemies, we read that upwards of fifteen thousand have been taken by fishermen in a single day at one of the fishing stations on the Russian rivers.[1] Many other instances of great fecundity among fishes might be given, but at least reference may be made to the testimony of Mr. Henry Lee, that a large Octopus produces in one laying, usually extending over three days, a progeny of from 40,000 to 50,000; and the same authority, confirming the observations of Johann Bodasch, found that in the mop-like mass of spawn belonging to a Squid (Loligo vulgaris) there were probably 42,000 perfect young Squids.[2]
Among mammals, the Rat is very prolific. Frank Buckland was told by a trustworthy Westminster ratcatcher that the Rat will breed every seven weeks, and that the female will begin to have young as early as fourteen weeks old.[3] The same author, referring to a little book on the Rat written by a Mr. Shaw, "of ratcatching notoriety," states that "his little dog Tiny, under six pounds weight, has destroyed two thousand five hundred and twenty-five Rats, which, had they been permitted to live, would, at the end of three years, have produced one thousand six hundred and thirty-three millions, one hundred and ninety thousand, two hundred living Rats."[4] "Every wild Rabbit who lives to old age has probably been concerned during its life as one of two partners in the production of not less than three hundred young Rabbits." Yet in England no perceptible increase is visible, and we must conclude "that out of three hundred Rabbits born, only two survive to middle age, on the average; the rest being either killed and eaten by carnivorous animals, or (more rarely) dying through inability, for some reason or another, to obtain food."[5] The Hamster (Cricetus frumentarius) possesses marvellous powers of reproduction, and frequently appears in count-
