ZOOLOGICAL GEOGRAPHY. 197 
tribution is decidedly in favour of Professor Huxley’s grouping 
of the regions into north and south—that is into Arctogza and 
Notogzea—rather than Dr. Sclater’s grouping of them into old 
and new worlds—that is into Palezogzea and Neogza—and that 
Tasmania, Patagonia, and New Zealand ought to form one region. 
Perhaps the best compromise between existing opinions would 
be the following :— 
1. Arctogzal Region. 
(a) Nearctic sub-region. 
(6) Palearctic sub-region. 
. Oriental Region. 
. Ethiopian Region. 
. Neotropical Region. 
. Australian Region. 
. Novozelanian Region. 
Onur BR WwW WH 
Mr. Wallace has shown that these regions represent very 
fairly the distribution of the butterflies, the carnivorous ground 
beetles, the stag beetles, and the lamellicorn beetles ; while the 
hawk moths, the Buprestride, and the longicorn beetles show 
several anomalies, especially in a connection between the 
Australian and Neotropical regions ; and the same thing is seen 
in the distribution of the frogs. Very little is known of the 
distribution of other groups of insects and of earth-worms, 
while the classification of the land mollusca is in such a state of 
confusion that we cannot.for many years know much about 
them. 3 
To account for the resemblances between the different 
southern: regions, Mr. Wallace has proposed ‘a very ingenious 
theory. It is, that all the principal groups of animals have 
originated in the Arctogzal region, and have spread in wave 
after wave southward into Africa, India, South America, and 
Australia ; while the new forms constantly arriving in Arctogea 
have successively exterminated the older ones. Thus Australia 
is inhabited by the descendants of an early wave of mammalian 
animals which have been preserved from destruction by the 
Australian region having become isolated from the large masses 
of land to the north, and the Neotropical, Ethiopian, and 
Oriental regions each contain remnants of the forms which once 
occupied Arctogzea ; while the Novozelanian region was cut off 
from Australia before any mammals had travelled so far south. 
The large amount of paleontological evidence which Mr. 
Wallace has accumulated is sufficient, I think, to prove this 
theory for the mammalia, and perhaps even for the struthious 
birds; but the distribution of both the ganoid fishes and the 
tailed amphibians is not in accord with it ; and for other groups 
of animals which are found in the south, but not in the north, 
we have no direct proof of a southerly migration. We must 
therefore, in these cases, be guided by other evidence, and can 
hardly accept Mr. Wallace’s theory as the explanation of every 
case of affinity between the regions of Notogea. 
