rhino cero tidæ, trhinoceridæ

pl. (Lat. rhinoceros (genitive rhinocerot(is), rhinocer( os ); fem. pl. adj. suff. -ido.] 1. Zool .: A family of Peri odactyl a (q.v.). Head large, skull elongated; brain cavity very small for size of skull; limbs stout and of moderate length. Three completely developed toes, each with distinct broad rounded hoof, on each foot. Mamme two, inguinal; eyes small; hairy covering scanty; one or two median horns on face, of a more or le coni cal form, and recurved, often growing to a length of three or even four feet, and composed of a solid hardened ma of epidermic cells, growing from a cluster of long dermal papillæ, which present the appearance of a ma of agglutinated hairs. One recent genus. [2.] Distribution now restricted to Africa and portions of the Indian and Indo-Malayan regions. 2. Palæont.: From the Miocene onward. Several forms have been discovered in America. Remains of a primitive peri odactylic form, from which the Rhinocerot i dae may have descended, have been found in the Eocene of the Rocky Mountains. Hyracodon and Aceratherium (with four toes), from the Miocene, had no nasal horn; Diceratherium, of the same age, had a pair of tubercles on the nasal bones, apparently supporting horns side by side. [RHINOCEROS, 2.]