The antelopes appear to stand, as it were, in a central position, surrounded by these three last-mentioned groups; in other words, there are species of antelopes that can scarcely be distinguished from goats, others equally like sheep, and others that come very near being true oxen! Nay, further, there are one or two species--the Gnus of South Africa--that bear a considerable resemblance to horses! At one time the antelopes were all classed in a single genus; but since the species have increased--or rather the knowledge of them--this arrangement has been deemed inconvenient; and the systematic naturalists have separated them into a great many genera--twenty or more--and to these genera they have given such a variety of pedantic titles, that it would be wellnigh impossible for one man's memory to retain them all. I do not hesitate to say, that it would have been much wiser to have retained the nomenclature of the old naturalists, and called all these animals _antelopes_--leaving the specific appellations to distinguish them from one another. In a popular sketch it is necessary to treat them in this way; for to give even a list of the generic characters of the systematic naturalists would occupy the whole of our space. First, then, of the number of these ruminants--that is, the number of kinds. In this respect they exceed the deer tribe, amounting in all to between eighty and ninety distinct kinds. Perhaps there are one hundred species upon the whole earth, since several new ones have been recently discovered in the interior regions of Asia and Africa. It is scarcely necessary to say that Africa is the great head-quarters of the antelope tribe--more than half the species belonging to that continent. In number of individuals, too, it far excels; the vast herds of these animals that roam over the karoos and great plains of South Africa consisting sometimes of numbers countless as locusts or the sands of the sea! Asia, however, is not without its share of species; and especially that portion of it--the Oriental region--so rich in other mammalia. In Australia no antelope has yet been found; nor even in the large island of Madagascar, so African in its character. Only one representative of the antelopes is indigenous to the New World--the Prong-horn of the prairies; for the Bighorn of the Rocky Mountains is a sheep, not an antelope. To say the least, this is a natural fact of some singularity; for from all we know of the habits of these animals, no country could be better suited to their existence than the great prairies of North America, or the llanos of the Orinoco, the paramos of Brazil, and the pampas of Buenos Ayres and Patagonia. And yet on these South American plains no animal of the genus _antelope_ has yet been discovered;--and on the prairies, as already mentioned, only one species, the Prong-horn.