THE LIFE OF MAMMALS 
sustaining the creature in the air when he spreads his limbs and 
makes his long leaps. We call it flight, but ‘‘sailing” is a more 
exact word, because there is no power of accelerating the speed, 
and little of changing direction; hence these animals may 
properly be regarded as offshoots of a wingless stock, which have 
developed the skin expansions as an aid in leaping, until now 
the smaller species 
will glide one hun- 
dred feet or so from 
some high limb to 
a lower one in 
another tree, and 
the big East In- 
dian round-tailed 
ones much farther. 
A recent discovery 
is that among the 
cliffs of the high 
western Himalayas lives a woolly flying-squirrel eighteen 
inches long, exclusive of the tail; and it was first described 
from a skin long used as a robe in a baby’s perambulator 
at Simla! 
There is to be found in Africa, only, a flying-squirrel so differ- 
ent in structure and relationships that it is held to represent a 
Kioma- separate order by some zodélogists, —the anomalurus 
beat; or “scaletail.”” Externally it looks much like an ordi- 
nary one; but its dentition is different, the cartilaginous support of 
the patagium extends from the elbow instead of from the wrist; 
and especially the under base of the tail is coated with a series 
of stiff, overlapping scales thought to be helpful in climbing. 
More lately a similar African animal has been discovered, 
peculiar in having almost no patagium, and considered by 
Lydekker® as representing the ancestral form from which 
sprang these queer imitators of our northern type. 
446 
Fisher, Phot. 
AMERICAN FLYING-SQUIRREL, 
