ADDITIONAL SIWALIK PERISSODACTYLA AND PROBOSCIDIA. 9 
ante-crocliet of tlie true molars is also smaller ; and tlie crocliet of m. 3 extends 
nearly, or comjDletely^ across the median valley. 
As it will be shown below that the Biigti teeth almost certainly belong to an 
Aceratherium, it will be unnecessary to point out the differences between them and 
the molars of the other species of Rhinoceros ; none of which resemble them very 
closely : and further comparisons may accordingly be confined to Aceratlierimn. In 
A . incisivum^ the upper molars very closely resemble the larger Bugti teeth ; the 
general plan of structure being precisely the same : the buttress is, however, 
somewhat more developed, the first costa placed more internally, the crochet larger, 
the tubercle at the entrance to the median valley generally less conspicuous, and the 
ante-crochet rather smaller in the European form ; these differences being most 
conspicuous in an early stage of wear.^ The premolars of the two are almost 
indistinguishable ; and the fossettes formed on the well-worn molars are likewise 
precisely similar. The mandible presents, however, considerable differences in the 
two forms ; the inferior border of the horizontal ramus of the European species® 
being straight, and the ramus itself preserving nearly the same vertical thickness 
throughout its length. The lower canines are much larger, and the cheek-teeth have 
a more distinct cingulum. Although these differences are in all probability of 
sufficient importance to indicate the specific distinctness of the two forms, yet the 
resemblances are so strong as to render it certain that they were extremely closely 
allied ; and it may, therefore, be inferred that the Bugti rhinoceros was in all 
probability an Aceratheriimi. 
It does not appear that the upper molars of any other European species of that 
genus ajDproach as closely to the Biigti teeth : those of A. lemanense,'^ and A. croizeti^ 
being distinguished by the larger buttress, and the absence of the crochet ; and the 
lower molars of the former® having a strongly developed cingulum. In A . goldfussi’ 
the upper molars have a conspicuous buttress, as in A. perimense : the ante-crochet is 
very slightly developed, and there is no tubercle at the entrance to the median valley 
of tn. 3 . A. velaunmif is readily distinguished by its shortened mandible, and the 
peculiar form of its lower molars. The upper molars of A. minutmn^ have a large 
buttress, and apparently no distinct tubercle at the entrance to the median valley. 
In the so-called R. austriacus^ Peters,'® of the middle miocene of Styria, which 
1 Kaup, “ Beitrage,” pt. 1., pi. IV. (the figure is very small, but being a photograph permits of enlargement with a lens : 
a cast of the original is in the British Museum). Blainville, “ Osteographie,” Genus Ehinoceros, pi. XII. (if. incisivus de 
Sansan). The teeth in Kaup’s specimen are slightly less worn than in the specimen represented in pi. I., fig, 1. 
2 Compare pi. I., fig. 2, with fig. 62 (p. 58) of “ Les Enchainements du Monde Animal — Mamm. Tert.” : the two teeth 
are in about the same stage of wear. 
3 Kaup, op. cit., pi. 6. 4 BlainviUe, “ Osteographie,” Genus Ehinoceros, pi. XII. {R. incisivus d’ Auvergne). 
3 Filhol, ‘Ann. d. Sci. Geol.,’ vol. XI., pp. 78-9. 6 Gaudry, op. cit., fig. 59. 
7 Kaup, op. cit., pi. II. Gaudry, op. cit., fig. 64 [R. brachypus). 
8 Eilhol, •“ Mammiferes Fossiles de Eonzon,” pi. XII. 9 Kaup, loc. cit. 
10 ‘ Denks. k. Ak. Wiss.,’ vol. XXX., 1870, p. 46, pi. II. In the second volume of the present work this species is ■ 
referred to Rhinoceros. 
C 
