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Show 1876.] DENTAL CHARACTERS OF RHINOCEROSES. 455 overhang the occipital surface of the skull. Nasal bones narrow and pointed anteriorly. A well-developed nasal and a small frontal horn separated by an interval. The skin thrown into folds, but not so strongly marked as in A. C E R A T O R H I N U S , Gray, P. Z. S. (1867)*. 1. C. SUMATRENSIS, Cuv. (R. A. 1817). C. sumatranus, Raffles(Trans. Linn. Soc. vol. xiii. 1822, p. 268). C. niger, Gray (Hand-list Edentates &c. Brit. Mus. p. 48, 18/3). 2. C. LASIOTIS, Sclater (P. Z. S. 1872, p. 493). (Anatomical characters unknown.) C. In the adults the incisors are either quite rudimentary or entirely wanting. The post-tympanic and post-glenoid processes not united below the auditory meatus. Occipital crest produced backwards, and overhanging the occipital surface of the skull and condyles. Nasal bones thickened and rounded or truncated in front. An anterior and posterior horn in close contact. Skin without any definite permanent folds. A T E L O D U S , Pomel (1853)f. a. Smaller size. Incisor teeth always present in the young, and sometimes persistent as rudiments through life. Molar teeth with crista and crochet rarely united. Front end of mandible deep and compressed. 1. A. BICORNIS, Linn. R. africanus, Cuv. (R. A. 1817). R. keitloa, A. Smith (Cat. S. A. Mus. p. 7, 1837). * These terms may be taken either as generic, or as indicating natural sections of the Linnean genus Rhinoceros. The great differences in the visceral anatomy (referred to above) between this species and the first, tend to support the former view. Their significance will, however, be better understood, when the internal anatomy of the third section is known, and also that of R. sondaicus. t Pomel divided the genus Rhinoceros, Linn., into three subgenera :-• 1. Acerotherium, Kaup. 2. Rhinoceros, Linn. 3. Atelodus, Pomel. The last is thus defined. " Os nasaux portant une ou deux cornes ; pied a trois doigts. Une ou deux paires d'incisives inferieures caduques en forme de simple tubercule souvent a peine sorti de la gencive, ou nulles; pas de plis a la peau sur les especes vivantes." The following are the species assigned to this group :- A. elatus (Croizet & Jobert) "j A. leptorhinus (Cuv.) | ext;nct_ A. tichorhinus (Cuv.) f A. aymardi (Pomel) J A. bicornis (L.) j A. keitloa (A. Smith) \ existing. A. simus (Burchell) J ("Catalogue methodique et descriptif des vertebres fossiles decouverts dans le bassin hydrographique superieur de la Loire," Part ii., in 'Annales scientifiques, litteraires et industrielles de l'Auvergne,' torn. xxvi. 1853, p. 114.) |
