Nasals long in early, but shorter in later forms, hornless; orbit open behind.
Hornless rhinoceroses, with five fronttoes, ranging from the Oligocene to the Lower Pliocene in Europe, represent the genus Aceratherium, which may also occur in America, as it certainly does in India.
Picticaudata form a group in which the females are hornless and the face-markings inconspicuous or wanting.
The Theban goat, of the Sudan, which is hornless, displays the characteristic features of the last in an exaggerated degree, and in the form of the head and skull is very sheep-like.
From this it seems probable that Palaeotragus and Ocapia indicate the ancestral type of the giraffe-line; while it has been further suggested that the apparently hornless Helladotherium of the Female Okapi.
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