BLACK-TAILED DEER. 99 
as impassable as a Chinese wall to an entire species of animals 
who have full physical power to traverse it, but do not, while 
all others pass it unhesitatingly, is certainly a curious and an 
interesting fact, well calculated to stimulate the naturalist to 
seek for the cause, which has hitherto eluded all inquiries. 
In its own home, this animal seems to be healthy, vigorous, 
and prolific, the females generally producing two and sometimes 
three at a birth. 
The bifurcated antler and the bounding gait observed in the 
mule deer, are found also to be characteristics of this deer, but 
they are strictly confined to these two species; nor is it easy 
to conceive why this laborious and fatiguing gait has not in 
the course of time given place to the more easy and enduring 
running pace of the Virginia deer, which inhabits the same 
country. 
Both these deer know how to gallop, and do so when not ex- 
cited and at a moderate speed; but when alarmed and seeking to 
make a rapid flight, they strike into the nervous bound, which 
although rapid at first, can be endured but for a short time, and 
is particularly laborious on broken ground. 
