Guide to the Galleries of Mammalia, 7th ed

The horns, the first of which is placed on the muzzle, differ essentially in structure from those of other Mammals, being composed of modified and agglutinated hairs.

This group is now restricted to the African and Oriental regions, but in former times was spread over all Europe, Asia, and America. One of these extinct forms (R. antiquitatis), a native of Europe and N. Asia, was invested with a coat of thick woolly hairs, like its contemporary, the Mammoth.