portions of the nose and mouth is shiny Vandyke brown and black, with a
strong tinge of bluish-purple, but this latter tint is not noticeable
save upon close examination, and the eyelid is the same. The iris is of
an irregular pear-shaped outline, 1-5/16 inches in its longest diameter,
very dark, reddish brown in color, with a black edging all around it.
Ordinarily no portion of the white eyeball is visible, but the broad
black band surrounding the iris, and a corner patch of white, is
frequently shown by the turning of the eye. The tongue is bluish purple,
as are the lips inside.

The hoofs and horns are, in reality, jet black throughout, but the horn
often has at the base a scaly, dead appearance on the outside, and as
the wrinkles around the base increase with age and scale up and gather
dirt, that part looks gray. The horns of bulls taken in their prime are
smooth, glossy black, and even look as if they had been half polished
with oil.

As the bull increases in age, the outer layers of the horn begin to
break off at the tip and pile up one upon another, until the horn has
become a thick, blunt stub, with only the tip of what was once a neat
and shapely point showing at the end. The bull is then known as a
"stub-horn," and his horns increase in roughness and unsightliness as he
grows older. From long rubbing on the earth, the outer curve of each
horn is gradually worn flat, which still further mars its symmetry.

The horns serve as a fair index of the age of a bison. After he is three
years old, the bison adds each year a ring around the base of his horns,
the same as domestic cattle. If we may judge by this, the horn begins to
break when the bison is about ten or eleven years old, and the stubbing
process gradually continues during the rest of his life. Judging by the