xlii INTRODUCTION. 
the larger continents, and which seems now to have disap- 
peared from the face of the earth. 
The genus Mastodon forms an exception to that conti- 
nental localization, not only of existing, but of pliocene 
extinct genera of Mammalia above briefly dwelt upon. 
The solitary character, however, of this exception serves 
rather to establish the rule: at least, I know of no 
other extinct genus of Mammal which was so cosmo- 
politan as the Mastodon: it was represented by species, 
for the most part very closely allied, if actually distinct, 
in Europe, in Asia, in North and South America, and in 
Australia: it is the only aboriginal genus of quadruped in 
Australia which was represented by other species in other 
parts of the world.* 
The most remarkable local existing Fauna, in regard 
to terrestrial vertebrated animals, is that of the islands 
of New Zealand, with which geologists have been made 
familiar by Mr. Lyell’s indication of its close analogy with 
the state of animal life during the period of the Wealden 
formation.+ The only terrestrial Mammalian quadruped 
hitherto discovered in New Zealand, whose recent intro- 
duction into that island is at all doubtful, is a small Rat. 
The unequivocally indigenous representatives of the warm- 
blooded vertebrata are Birds, of which the Apteryz is the 
most peculiar. It is the smallest known species of the 
Struthious or wingless order, has the feeblest rudiments of 
the anterior members, and not any of its bones are per- 
meated by air-cells. This bird forms the most striking 
and characteristic type of the proper or primitive Fauna of 
New Zealand. 
* See * Report on Australian Fossil Mammalia,’ in the ‘ Transactions of the 
British Association,’ 1844, p. 239. 
+ ° Elements of Geology,’ 8vo, 1838, p. 366, and Principles of Geology,’ 1837, 
vol. 1. p. 204. 
