668 
AFRICAN GAME ANIMALS 
In size the sexes are very similar, the male exceeding the 
female but little. The only appreciable secondary sexual 
characters are found in the size of the horn bases, the nasal 
bones which support them, and the general massiveness of 
the skull. The base of the front horn in the male is always 
greater than in the female, this dimension showing no rela¬ 
tionship to the length of the structure. The width of the 
nasal boss which supports the front horn is correspondingly 
greater in the male. Male skulls are usually actually wider 
than those of females and are always relatively so as well as 
being longer. So marked are these sexual characters in 
the skulls that they can be sexed with a fair amount of 
certainty. 
The species is normally two-horned, the front horn 
greatly exceeding the rear one in size. The front horn is 
situated on a prominent bony boss at the tip of the nasal 
bones and is immediately followed by the rear horn which 
is much compressed laterally and placed on the suture 
between the nasal and frontal bones. The front horn is 
squared in front where it partakes of the shape of the snout, 
and is normally curved backward as in the black rhinoceros. 
The usual length of this horn is two feet although occa¬ 
sional specimens attain a length of five feet. The record 
horn for the South African race is sixty-two and one-half 
inches. Such enlarged horns are attained only by the fe¬ 
males in which they project forward in advance of the snout. 
The rear horn is usually low, sharply conical, and con¬ 
siderably compressed. It seldom exceeds more than a few 
inches in height and is occasionally wanting. The rear 
horn never approaches the front one in size as in the keitloa 
variety of the black rhinoceros in which the two horns are 
equal in size. The rear horn is so small that it is obviously 
disappearing, the species showing a marked tendency to 
become single-horned; but actual single-horned specimens 
are rare. 
The only parts of the body which show a growth of hair 
are the terminal margins of the ears and the apical one- 
fourth of the tail. The hair of the ears is quite soft and an 
inch or so in length. The hair covering of the tail is stiff 
and bristly, and confined to a streak along both edges of 
the flattened tip. In the two male skins the hair covering 
