ADDITIONAL SIWALIK PERISSODACTYLA AND PROBOSCIDIA. 5 
in plate I., fig. 7, that the buttress is much more strongly developed ; the second 
costa (c) standing out more prominently, and the first costa [d) being placed more 
internally to the plane of the external surface of the crown, and more prominently 
developed. Again, the anterior collis [a) has no vertical groove on its posterior side, 
and the ante-crochet (/) is absent : the crochet [e) is also relatively larger, and the 
outer termination of the median valley in an early stage of wear^ is triangular, 
instead of rounded. The posterior valley (^) of JR. sivalensis forms a deep, round 
pit, instead of a shallow, elongated pit ; while there is no tubercle at the entrance to 
the median valley [g). The figures of the more worn teeth of R. sivalensis given in 
the ‘ F.A.S. show that the fossettes formed on their crowns are quite different from 
those of the Biigti specimens. The premolars of the former species® are, moreover, 
quite distinct from those of the latter, having no cingulum on the inner side, and a 
well-developed second costa. 
These comparisons leave no doubt of the well-marked distinctness of the 
present specimens from the typical race of R. sivalensis. In the second volume,^ 
however, a right upper molar from Sind was described, presenting certain differences 
from the typical teeth of the last-named species ; but apparently not such as, in the 
absence of other evidence, could be taken to justify specific distinction. This 
specimen is refigured in plate I., fig. 3. In the general contour of the crown, 
especially in the well-developed buttress and costse, this tooth agrees with the typical 
molar of R. sivalensis. It differs, however, in that there is a groove on both sides of 
the anterior collis (a), with the consequent formation of a small ante-crochet ; by 
the elongated and shallow form of the posterior valley (^) ; and by the presence of a 
rudimentary tubercle at the entrance to the median valley [g). In the same volume® 
another upper molar, of considerably smaller size, but presenting the same external 
contour of the crown, was described, and provisionally referred to R. sivalensis under 
the separate varietal name of gajensis (so named from the Graj beds, in which it was 
found). This specimen is refigured in plate I., fig. 4. In this tooth the characters 
in which the last sj)ecimen differed from the typical molar of R. sivalensis are 
exaggerated ; the ante-crochet being very distinct ; the posterior valley (^) much 
elongated; and the tubercle at the entrance to the median valley (^) distinctly developed. 
If the tooth represented in pi. I., fig. 3, had not been known, the Gr4j tooth 
would have been certainly referred to a distinct species : but as the former, which in 
future it may be convenient to refer to as R. sivalensis, var intermedins, is precisely 
intermediate between the latter and typical teeth of R. sivalensis, it was found 
advisable to provisionally regard the three as races, or varieties, of the same species : 
this conclusion being strongly confirmed by the circumstance that the teeth regarded 
as the milk-molars of R. sivalensis^ closely resembled the Ghj tooth. 
It will be observed that the molars of v. intermedins and v. gajensis resemble the 
1 Compare pi. I., fig. 2, ■with fig. 7 ; these specimens being in nearly the same stage of wear. 
2 Plates LXXIV., fig. 5 ; LXXV., fig. 5. 3 Supra,, vol. II., pi. V., fig. 6. 4 Page SO. 6 Page 40. 
6 Vol. II., pi. VI., fig. 2. 
B 
