RHINOCEROS. 595 



01 tiiv. Rhinoceros tichorhinus. It most nearly resembles the one- 

 horned Indiau i?binoceros in the pattern of the grinding surface of 

 the molars, the valley ,m has at first the same contracted beginning 

 and expanded bilobed termin...,^^ ^^^ ^1^^ -^^^^^ ^^^ -^ ^^^^^^ ^^ 

 the cuttmg off of the hinder lobe, r., 7 ^^ ^ corresponding molar 

 of the Rhinoceros leptorhinus, which in the --.,1(3^^^^ of its upper 

 molars, most nearly resembled the Sumatran Kir.,^ _ ,, 



valley (&) has the same wide beginning and contracted eno, i_^j , 

 is wholly insulated at c by the obliteration of the enamel covering 

 the shallow part of the valley between the end of the secondary 

 process /, and the anterior lobe or ridge of the grinding surface : 

 the upper molars of the Rh. leptorhinus are further distinguished 

 from those of the Rh. tichorhinus by the longer ridge {n) along the 

 base of the anterior side, and by the narrow prominent longitudinal 

 ridge 0' on the outer side of the crown. Both the above-named 

 extinct species of Rhinoceros have left their remains in England as 

 wxll as on the continent. The Rh. incisivus, which has not hitherto 

 been found in British strata, is readily distinguished by the more 

 simple form and almost uniform width of the valley b ; and still better 

 by the basal ridge which is continued from the anterior side along 

 the whole of the inner to the posterior side of the crown of the 

 molar, at some distance above the basal termination of the enamel ; 

 in these modifications it offers the nearest approach to the con- 

 figuration of the upper molars in the Pal<sotherium. This basal 

 ridge is also well developed in the molars of the Hyrax. 



There are corresponding, but less marked differences in the 

 molar teeth of the lower jaw of the different species of Rhinoceros ; 

 on which, however, T shall not here dwell. The first premolar is 

 the smallest and simplest ; the bilobed structure is at best feebly 

 indicated by the undulations of the outer surface : and on the inner 

 surface, by a simple depression or a notch : in the Sumatran Rhino- 

 ceros the notch is near the front margin of the tooth ; it affords 



posterieure commence aetre cernee," p. 57. And the tooth (PL 13S, fig. 7) figured in his 

 PI. xm, fig. 4, as follows : " Fig. 4, PL xiii, est un sixieme du cote gauche, pea usee, des 

 Crozes, De'partement du Gard. Le trou anterieur y est deja distinct par Funion du crochet 

 de la colline posterieure avec la colline anterieure, mais I'echancrure posterieure n'y est point 

 encore cernee." 



Q Q 2 



