286 MAMMALS. 



all iDrobabiHty, formerly consisted of three large islands, — the north, the east, and the south- 

 west. This is the inference from the geological data. There are these three isolated masses 

 of land more or loss surrounded by tertiary deposits which of course must have been under water 

 when deposited. Let us see how the zoological data correspond with the geological. 



The chief groups or genera into which the Marsupials are divided, may be taken in the follow- 

 ing order: 1. The Antcchini ; 2. The Phascogales ; 3. The Dasyuri ; 4. The Opossums; 5. The 

 Phalangors ; 6. The Petaurists or Flying Phalangers ; 7. The Wombat ; 8. The Kangaroos and 

 Hypsiprymni ; 9. The Peramelidao; 10. Tarsipes ; and 11. Myrmecobius, leading to the next 

 order, the Monotremes. 



Antechini. I have already drawn attention to the perfect outward resemblance which these 

 insectivorous marsupials bear to the common Mice, Eats, and Jerboas. {See Frontispiece.) The majority 

 are found in the eastern district (seven in New South Wales, and four in Yan Dieman's Land), 

 one is found in New Guinea in extension of this range. Five species occur in Western Australia ; 

 but not one of these species is found on the other side of the Continent. Three, however, which 

 are found in South Australia, belong also either to the east or to the west. 



Phascogale. These, although insectivorous and usually considered equivalents of some of the 

 placental Insectivora, have fully more external resemblance to the Rats and Mice, although this 

 is more markedly the case with the last genus, Antechinus, which Waterhouse considers only a 

 part of it; — an opinion, however, which is not shared by Mr. Goidd, who thinks that they have 

 no connexion with each other. We only know three species of the restricted Phascogale. The 

 genus especially affects the interior, and the species have been foxmd respectively on tlie outskirts of 

 New South Wales, South Australia, and West Australia. 



Dasturus axd Thylacinus. — Tasmaxian Devils, Tigers, &c. (Map 97.) — Van Dieman's Land is 

 the stronghold of these carnivorous marsupials, four out of six being found there, and three being 

 peculiar to it. Another is peculiar to the northern district of Australia. The other two extend 

 into New South Wales, and one of them ranges both through it and South Australia and West 

 Australia. Remains of an extinct Dasyurus and an extinct Thylacinus have been found in the 

 bone-caves of Wellington Valley. 



Opossums. (Map 96.) The Opossums seem to come most naturally next to the Phascogales. 

 They are a very homogeneous group, alien to Australia. They all belong to the New World, and 

 their range is very extensive, both in North and South America. In South America the genus occurs 

 in much the greatest abundance in Brazil, two-thirds of the whole being found there, or twenty-two 

 out of thirty-two. None are found in Patagonia, the La Plata river forming their southern boundary ; 

 one occurs in Chili, and seven in Peru (three of which are on the west side of the Andes), six in 

 Paraguay, Seven in Guiana, two in Mexico, one of which extends into California, and one in the 

 Eastern United States of North America, but not further east than the Hudson. Not one of the 

 species met with on the one side of the Andes occurs also on the other. Not that the height of 

 the Cordillera in itself presents an absolute barrier to the passage of Opossums from the one 

 side to the other, because Tschudi mentions one species (Didelphys Azarje) which was killed 

 at an elevation of 12,500 feet above the level of the sea, and although that species is not suited 

 to the hot and wooded valleys, it might be the progenitor of species that were. Only two 



