114 ZOOLOGICAL GARDENS. 
tion of the spinous processes of the vertebre beneath. 
It is covered, as well as the greater part of the head, 
the neck, and the shoulders, by a thick shagey coat 
of long woolly hair. The rest of the body is clothed 
only by short close curling hair, which becomes rather 
woolly in the depth of winter, and falls off almost 
entirely in the summer, exposing the black wrinkled 
skin beneath. The colour of the animal is in general 
of a deep brown approaching to black, but darker on 
its hinder parts, black on the head, and lighter about 
the neck and shoulders. The legs are short, firm, and 
muscular; and the tail, which is little more than a 
foot in length, is nearly naked except at the tip, 
where it is terminated by a tuft of long black hairs. 
The head is so extremely large and heavy as to require 
a high degree of muscular force for its support; and 
for this purpose the great developement of the spinous 
processes of the dorsal vertebre, and of the powerful 
muscles attached to them, appears to be admirably 
calculated. The eyes are small, black, and piercing. 
The horns are short, black, thick at their base, placed 
widely apart from each other, directed outwards, back- 
wards, and upwards, and but little curved towards 
their tips. The female is considerably smaller than 
the male, her mane is much less developed, and her 
horns are much less strongly formed. 
There is one particular in the anatomical structure 
of the Bison which must be regarded as decisive of its 
specific distinction. In the Common Ox it is well 
known that the number of ribs on either side is thir- 
teen; in the Aurochs it is fourteen; and in the Bison 
fifteen ; the supplementary ribs in the two latter animals 
being attached to the anterior lumbar vertebree, which 
thus become dorsal in their functions. Such a variation 
never occurs as a permanent structure in breeds origi- 
