Page:Natural History (1848).djvu/259

ists in the case of the Opossums, the most highly developed form of Marsupialia, whose home is South America, one or two species reaching into the southern provinces of the northern continent: and it is worthy of observation that the same region is the great abode of the lowest order of Placentalia, the Edentata; which we have just dismissed.

Mr. Waterhouse, whose attention has been much directed to these interesting animals, divides the sub-class into eight Families,—Dvdelphide, Dasyuride, Myrmecobiude, Peramelide, Macropodide, Phalangistide, Phascolomyide, and Monotremata. It may be doubted, indeed, whether these might not with propriety, take the rank of Orders, were it not for the limited number of the species, which makes it more convenient to con- sider them as Families. Perhaps, however, we may more correctly group the whole into two Orders; as the animals designated by the last term, seem to differ much more widely from all the others than those do from each other.