i8770 
Southern Hemisphere. 
353 
Australia, is probably due to a great destruction of the 
native species during the Glacial period, and the arrival 
since of several from the countries to the north-west. I do 
not know how else some of the faCts can be explained, such 
as that of there being only eight butterflies, and amongst 
these some of wide distribution ; and that of the Hete- 
roptera there are thirteen known species belonging to thirteen 
different genera and nine distinct families.* Such gaps as 
these in the fauna of a country are as significant as the 
grooved and polished surfaces of its rocks, and the naturalist 
may as surely point to the evidences of the Glacial period 
as the geologist. 
Mr. Wallace has also drawn attention to the large 
destruction of species of insects in the Chilian sub-region, 
evidenced by the great number of peculiar genera of beetles 
of extremely isolated forms, and I might multiply instances 
from the faunas and floras of southern lands, all tending to 
the conclusion that the southern hemisphere has been gla- 
ciated as much as, or more than, the northern ; but I could 
not do justice to this phase of the question within the limits 
of this article, and I have only glanced at some of its most 
salient points with the objecft of indicating that the physical 
evidence of glaciation does not stand alone, but is strength- 
ened by that of the present distribution of animal and 
vegetable life. 
* Capt. Hutton, Trans. New Zeal. Inst., vol, v., p. 227. 
Z B 
VOL. VII. (N.S.) 
