SIWALIK MAMMALIA 
11 
show the same narrow muzzle, with a sudden expansion of the maxilla at the 
infraorbital foramen ; in both the orbit is large with a notch below the level 
of the supraorbital foramen ; the horn-cores are similarly situated in respect to 
the orbits, with a considerable interval between them, and directed at their bases 
upwards and backwards ; there is also the same concave facial profile in the orbital 
region, and the same strongly-marked ridge descending from the orbit to the first 
true molar. The palate is generally similar in the two, but the anterior pair of 
basioccipital tubercles are more approximated in the fossil ; both present the same 
deep concavity in the median line in advance of the premolars. The upper molars 
of H. niger have very broad and nearly square crowns, presenting a remarkably 
bovine structure ; the outer surface of each lobe is relatively wide, with a strongly- 
marked median costa, and there is a large internal accessory column, of which the 
inner termination is expanded antero-posteriorly. 1 The imperfect protrusion of the 
molars of the fossil specimen renders their distinctive features obscure, but mm 4 
agrees in general characters with those of the existing species. The united length 
of m. 1 and m. 2 is nearly the same as in II. niger, and thus indicates that adult male 
specimens of the fossil were about equal in size to that species. On the assumption 
that the Calcutta specimen is specifically the same as the British Museum cranium, 
it will probably indicate a female individual. 
Affinities. — The resemblance between the British Museum Siwalik cranium and 
that of H. niger is so close as to leave little doubt that the two species are generically 
the same, and in any case that they are very closely allied. No other fossil species 
of the genus appear to have been recorded ; and of the existing species II. niger and 
E. leucophceus are confined to south Africa, while H. equinus ranges into Nubia and 
the adjacent districts. 
Genus. Gazella, Blainville. 2 
Distribution. — This genus has a wide distribution at the present day, being most 
abundant in the deserts on the borders of the Palaearctic, Oriental, and Ethiopian 
regions; its range in Europe extends from the lower pliocene of Pikermi to the 
Norwich Crag. 3 
Species. Gazella porrecticornis, nobis! 
Syn. Antilope porrecticornis , nobis. 5 
History. — This species was founded upon the left half of a frontlet and horn- 
core figured in vol. I. pi. XXV. fig. 4, which was there stated to be allied to the 
gazelles, and was subsequently referred to the present genus. 6 
Frontlet. — The type specimen is represented in the accompanying woodcut 
(fig. 2), the right half having been restored. The frontal is complete with the 
1 The inner expansion of this column at once distinguishes the molars of Hippotragm niger from those of Boselaphus, in 
which the crowns and the base of the outer surfaces of the lobes are relatively narrower. 
2 ‘ Bull. Soc. Philom. Paris.’ 1816. p. 75. 3 Q. anglica, Newton. 
4 Supra vol. I. p. 158 (1878) — Antilope. 
6 See “Cat. Foss. Mainm. Brit. Mus.” pt. II. p. 50. 
5 Loc. cit. 
