FORM AND SIZE. 119 
is less so than the Lapland reindeer. This is shown more clearly 
by a reference to the illustrations than could be done by any 
verbal explanations. 
The next in size to the woodland caribou comes the Mule Deer 
of the Rocky Mountains and the West. This animal rarely at- 
tains a live weight exceeding two hundred and fifty pounds, 
though individuals have been killed exceeding this; still the 
average is much less. Its head and neck are well proportioned, 
though its enormous ears greatly disfigure it; its body is long 
and well poised; its legs are long, straight, and rather heavy. 
Its unsprightly action contributes more to its awkward appear- 
ance than any disproportion of its members. 
There is a great difference in size among individuals of the 
species, depending much on the altitude of their habitat, those 
inhabiting the higher elevations being the largest. I have re- 
ferred in another place to a remarkable variety of this species 
found by Mr. John Xantus, as [am informed by Professor Baird, 
one of the most reliable collectors for the Smithsonian Institute, 
who forwarded several specimens to Washington from Cape St. 
Lucas, in Lower California. With all the other indicia of the 
Mule Deer, they are very diminutive in size, and have spike an- 
tlers about six inches in length. This is one of the most remark- 
able modifications of a well-established species to be met with, 
which we must attribute to peculiar conditions of life; and yet 
Tam not fully informed what these peculiar conditions are which 
produce this remarkable physical change. If mere size and 
peculiarity of antler were alone sufficient to establish a specific 
distinction, we should be justified in pronouncing these to be a 
distinct species. I have not been able to learn that this diminu- 
tive Mule Deer has been met with except in the lower part of 
the peninsula, and the extent of its habitat there is as yet uncer- 
tain. In connection with this deer, this fact should be remem- 
bered. 
The average size of the Columbia Black-tailed Deer is but little 
greater than that of the common deer, and I have heard of no 
individuals having been met with as large as some of the latter 
species. Its limited range may explain its greater uniformity in 
size. It is probably rare to meet an individual whose live weight 
would reach one hundred and fifty pounds, while the average of 
adults would be considerably below that figure. 
It has a broad head, with a large and brilliant eye. Its ears 
are large, but not so disproportioned as to attract attention. Its 
