242 MOSTLY MAMMALS 
less well acquainted with mammals, so far as their exteriors 
are concerned, than he is at the present day. And 
although he had a suspicion that the skin in question 
was peculiar, no steps were taken to ascertain whether 
this was really the case. One day, however, in 1888, 
when paying a visit to the Natural History Museum, he 
was shown a living flying-squirrel from Astor, remarkable 
for its dark colour and bushy tail, which was pronounced 
to represent a then unknown species. A brief inspection 
was sufficient to render it evident that the skin serving as 
a perambulator-rug belonged to the same species as the 
living animal, although a much larger and finer individual. 
It was soon after presented to the Museum, and described, 
in conjunction with the complete specimen, not only as 
the type of a new species, but of a new genus, under the 
title of Eupetaurus cinereus. Owing to the splendid de- 
velopment of the tail in the flat skin, the figure of which 
a reproduction is given in the plate was partly drawn 
from that specimen. 
The main reason for making the woolly flying-squirrel 
(as, from the nature of its coat, it has been called) the 
type of a genus by itself is afforded by the characters of 
its cheek-teeth, which differ from those of other members 
of the group by their tall crowns and imperfectly developed 
roots. This character indicates greater specialisation than 
the ordinary flying-squirrels. Unfortunately little or 
nothing is known as to the life-history of this splendid 
representative of the flying-squirrels, but there is some 
reason to believe that it dwells, at least to a certain extent, 
among rocks rather than in trees. 
Although they do not properly come within the scope 
of the present article, a few words may be said with 
regard to the flying-phalangers (the flying-squirrels of the 
