rhinocerotidæ

from The Century Dictionary.

• A family of perissodactyl ungulate mammals, for the most part extinct, typified by the genus Rhinoceros. The nasal region is expanded or thrown backward, the supramaxillary bones forming a considerable part of the border of the anterior nares, and the nasal bones being contracted forward or atrophied. The neck is comparatively abbreviated. The molar crowns are traversed by continuous ridges, more or less well defined, the upper ones having a continuous outer wall without complete transverse crests; the incisors are reduced in number or entirely suppressed. The basioccipital is comparatively broad behind and narrow forward; the tympanic and periotic bones are ankylosed and wedged in between the squamosal, exoccipital. and other contiguous bones. The only living genus is Rhinoceros, from which Rhinaster and Atelodus are sometimes separated. There are several extinct genera, as Cœlodonta, Acerotherium, Badactherium, and Hyracodon. The family is one of only three which now represent the once numerous and diversified suborder Perissodactyla, the other two being the Tapiridæ or tapirs and the Equidæ or horses. See cuts under Perissodactyla and rhinoceros.