U1 NOTOGAEA, NEOGAEA, AND ARCTOGAEA 85 
the realm of Notogaea), and Madagascar; and finally, the realm 
of Antarctogaea or Atheriogaea, which embraces New Zealand, 
the Antarctic continent, and a series of islands such as South 
Georgia and Kerguelen, and possibly even the extreme south of 
Patagonia. This latter quarter of the globe will need no further 
reference, as it has no truly indigenous terrestrial mammalian 
inhabitants. We cannot include the Bats in this statement, as 
their distribution is due to different powers of extending their 
range, and to different barriers from those which govern the 
range of other groups of mammals. 
(1) Notogaea."| This realm is characterised by the exclusive 
possession of the Monotremes :—that is to say, one of the two 
primary divisions of the Mammalia is absolutely restricted to 
this area. It contains, moreover, the vast majority of the 
Marsupials. Further, the realm of Notogaea is to be dis- 
tinguished by the entire absence of the higher mammals, with 
the exception of a few small Rodents. (The Bats are ignored 
for the reasons stated, and the Dingo is believed to have been an 
importation.) It cannot be disputed that this is a very distinctly- 
marked area of the earth’s surface. 
(2) Neogaea. The continent of South America has no 
Monotremes and only a few Marsupials, all of which, with the 
exception of Caenolestes, belong to the Polyprotodont division of 
that order, and to a peculiar family, Didelphyidae. The recent 
discovery of other fossil Marsupials, however, to some extent 
favours Huxley’s view that Neogaea and Notogaea form one 
realm as opposed to the rest of the world. Besides this, 
Neogaea possesses the Edentata, which are found nowhere else ;— 
that is, the division of the Edentata to which the name is 
now restricted by some authorities. It is also characterised by 
the nearly entire absence of the important order of Insectivora ; 
and, as minor marks of distinction, by the absence of Antelopes, 
Oxen and Sheep, of the Ichneumon tribe, of Horses, and of Lemurs. 
It has the exclusive possession of the Hapalidae and Cebidae, 
and of several families of Rodents. 
(3) Arctogaea, This vast realm is clearly capable of sub- 
division into four regions, which will be considered in detail 
later. In the meantime the points of likeness between these sub- 
divisions is more marked than are either the resemblances or the 
1 This term is sometimes used in a wider sense ; cf. vol. viii. p. 74. 
