well as aspect, as to justify in some degree the mistake. Let us take two of the greatest animals as examples,--the elephant and the rhinoceros. Buffon confounded the African with the Asiatic elephant. We now know that they represent two well marked species, _Elephas Africanus_ and _Elephas Indicus_; and that an ark which contained the ancestors of all the existing animals would require to have its _two_ pair of elephants, not the one pair only which would have been deemed sufficient eighty years ago. Again, with respect to the rhinoceros, Buffon was acquainted with the single horned animal, and had _heard_ of the animal with two horns; and so, though by no means certain that the "_variety_ was constant," he yet held that "two distinct species might possibly be established." But we now know that there are six species of rhinoceros (seven, according to the "Physical Atlas,")--_Rh. Indicus_, _Rh. Javanus_, _Rh. Sumatrensis_, _Rh. Africanus_, _Rh. simus_, and _Rh. ketloa_; and that, instead of _possibly_ four, at least twelve, or more probably fourteen, animals of the genus would require, on the hypothesis of a universal deluge, to have been accommodated in the ark. Buffon even held that the bison of America might be identical with not simply the auroch of Europe, which it closely resembles, but with even the European ox, which it does _not_ resemble. But it is now known, that while the European aurochs are provided by nature with but fourteen pairs of ribs, the American bison is furnished with fifteen. Of each of the ruminants that divide the hoof, there were _seven_ introduced into the ark; and it may be well to mark how, even during the last few years, our acquaintance with this order of animals has been growing, and how greatly the known species, in their relation to human knowledge, have in consequence increased. In 1848 (in the first edition of the "Physical Atlas") Mr. Waterhouse estimated the oxen at thirteen species; in 1856 (in the second edition) he estimates them at twenty. In 1848 he estimated the sheep at twenty-one species; in 1856 he estimates them at twenty-seven. In 1848 he estimated the goats at fourteen species; in 1856 he estimates them at twenty. In 1846 he estimated the deer at thirty-eight species; in 1856 he estimates them at fifty-one. In short, if, excluding the lamas and the musks as doubtfully _clean_, tried by the Mosaic test, we but add to the sheep, goats, deer, and cattle, the forty-eight species of unequivocally _clean_ antelopes, and multiply the whole by seven, we shall have as the result a sum total of one thousand one hundred and sixty-two individuals,--a number more than four times greater than that for which Raleigh made provision in the ark, and considerably more than twice greater than that provided for by the students of Buffon. Such is the nature and amount of the increase which has taken place during the last half century in the mammaliferous fauna.