66 ZOOLOGICAL GARDENS. 
Buffalo, which are no longer to be found in a state of 
nature, have been industriously propagated, under the 
auspices of man, throughout almost every part of 
the surface of the globe. The Yak alone, of all the 
domestic species, remains confined within its primitive 
limits, in Thibet namely and a part of Tartary, where 
it is said to be generally cultivated, almost to the 
exclusion of every other race. 
The characters by which the strongly marked group 
of animals thus associated together are distinguished 
from the neighbouring tribes, are, like most of those 
which serve to subdivide the great family of the Rumi- 
nants, of a very subordinate description. Their horns 
are common to both sexes, simple in their form, curved 
outwards at the base and upwards towards the point, 
and supported internally by bony processes arising 
from the skull, having cavities within them commu- 
nicating with the frontal sinuses, which are largely 
developed. Their muzzle is of large size; the skin 
along the middle of the neck and chest forms a pendu- 
lous dewlap of greater or less extent; and the general 
robustness of their make is strikingly contrasted with 
the lightness and elegance of form of some of the 
nearly related groups. 
In enumerating the species of which this genus is 
composed we have abstained from mentioning the Zebu 
or Indian Ox, simply because we do not consider it 
entitled to hold that rank in the scale of nature. There 
can be little doubt that it is merely a variety of the 
Common Ox, although it is difficult to ascertain the 
causes by which the distinctive characters of the two 
races have been in the process of time gradually pro- 
duced. But whatever the causes may have been, their 
effects rapidly disappear by the intermixture of the 
breeds, and are entirely lost at the end of a few gene- 
