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1. The Order Edentata contains about thirty-eight species, referable to fourteen genera and five families.
2. The Order is predominantly Neotropical, three of the families (the Sloths, Ant-eaters, and Armadilloes) with twenty-nine out of the thirty-eight species being confined to this Region.
3. Of the two remaining families one (the Aard-Vaarks) is purely Ethiopian, and the other (the Pangolins) is common to the Ethiopian and Oriental Region.
DISTRIBUTION OF MARSUPIALS AND
SECTION I.-INTRODUCTORY REMARKS
THE distribution of the two lowest orders of mammals, at which we have now arrived, is a comparatively simple matter, as these primitive creatures, which, according to the views of the highest authorities, form two primary subclasses of the whole class of Mammals (Metatheria and Prototheria), are confined exclusively to two of the great Zoological Regions of the earth. We will, nevertheless, pass the different families and the principal genera of these two orders in short review, and endeavour to point out the principal known facts of their distribution.
SECTION II.-DISTRIBUTION OF THE MARSUPIALS
The Marsupials have, until recently, been classified in six families, five of which belong to the Australian and one only to the Neotropical Region, and such was the plan of arrangement adopted for them by Mr. Thomas in his excellent catalogue of this group of mammals published in 1888. But great discoveries in this class have been made during the past ten years. A new Marsupial, of a most
remarkable form of structure, necessitating the formation of a new family, has been found in Australia, and Mr. Thomas himself has shown the necessity of adding to the Neotropical section a Marsupial which is more allied to the Australian forms than to those previously known from America, and which necessitates the creation of a second Neotropical family. We have now, therefore, to deal with eight families of Marsupials, six of which belong to the Australian Region and two to America. These families embrace altogether about 172 species, of which 144 are Australian and 28 are American. According to Mr. Thomas's arrangement, these are divisible into two large groups, the Diprotodonts, which are mostly vegetable-eating animals, and the Polyprotodonts, which feed generally on flesh and insects.
SECTION III.—DISTRIBUTION OF DIPROTODONT
The Kangaroos, or Macropodide, which form the first family of the Diprotodont section, are a numerous group embracing altogether more than sixty known species. These are distributed all over the Australian Region, but are specially abundant in Australia, where, as is well known, the Kangaroos form one of the most striking features of its peculiar mammal-life. In New Guinea and the Papuan Islands Kangaroos are by no means so abundant, especially those of the genus Macropus and the larger allied forms. On the other hand Dorcopsis and other smaller forms of Kangaroos range through the Papuan Sub-region up to Wallace's line, and New Guinea is especially peculiar for its Tree-kangaroos (Dendrolagus), although this genus likewise occurs in the tropical forests of Northern Queensland.
The second family of Diprotodont Marsupials—the Phalangers (Phalangeridæ) is likewise diffused over the whole Australian Region, and has even crossed the dividing line into Celebes, which, as already shown, must be included in the Oriental Region in spite of its possessing this single Marsupial form. This family contains some thirty-five species divided into twelve genera.
The typical genus Phalanger is a characteristic form of the Papuan Subregion, and only touches Australia at its northern extremity. It is of this genus that two species (P. ursinus and P. celebensis) occur in Celebes, to which island and the adjacent Sanghir Islands, so far as is at present known, they are restricted. Two of the genera of this family are so distinct from the remainder as to be generally assigned the rank of sub-families of themselves. These are the curious little Tarsipes, restricted to Western Australia, and the Koala, or native Bear (Phascolarctus), which is widely distributed in Eastern Australia but does not occur outside of it.
Next to the Phalangers we must, I suppose, place the new family of American Marsupials called by Mr. Thomas Epanorthidæ, as he refers the single genus yet known of it to the extinct Epanorthidæ of Ameghino, which he considers ought to include the recent as well as the fossil members of that nearly extinct group. According to Mr. Thomas the Neotropical Cænolestes is clearly a Diprotodont Marsupial, as not only does it possess the characteristic development of the lower incisors, but even its molar teeth resemble most closely in structure those of certain members of the Australian family Phalangeride.