THE OX AND ITS KINDRED 
A second family {Giraffidce) is formed by the 
giraffes and okapi, in which the horns take the 
form of permanent skin-covered prominences compar- 
able to the pedicles of the deer, and in the case of 
the male okapi surmounted by small caps of bare 
bone representing the cervine antler. 
A third type is represented solely by the North 
American prongbuck, or prong-horned antelope, in 
which the appendages take the form of forked hollow 
sheaths of horn borne on unbranched bony cores 
arising from the frontal bones, the cores themselves 
being permanent, but the sheaths annually shed. 
The whole structure, core and sheath together, forms 
the horn. Very generally the prongbuck is regarded 
as forming a family by itself — the AntilocapridcE \ but 
some naturalists are of opinion that it should be 
classed as a subfamily of the bovine group. Which- 
ever view be preferable, it is simpler to regard the 
species as representing a family. 
The remaining members of the typical ruminants 
constitute the family Bovidce^ of which the ox itself 
is the type. In all these animals the horns are of the 
same general type as those of the prongbuck, but 
their sheaths are unbranched and retained through- 
out life. The simplest type is that of the little 
African duikerboks, in which the horn forms a simple 
spike with a solid core. The more complicated spiral 
and ridged horns, like those of the kudu of Africa, 
appear to have been modified to resist strain and 
torsion ; but among these there is great variation, 
the cores of some, like the Russian saiga antelope, 
being solid throughout, while those of others are 
spongy in internal structure. 
It will frequently be found convenient to allude 
