SIWALIK AND NARBADA BUNODONT SUINA. 
63—97 
form of H. scemmeringi, and therefore larger than all other forms except H. waterhousi^ 
and the nnfigure.d American H. 'platyo'ps. From H. waterhousi (and II. typus) the 
Sind form is distinguished by the structure of its molars, but it cannot be compared 
with H. platgops. That it was closely allied to II. soemmeringi is pretty evident, but 
the materials at hand are insufficient to determine definitely whether the two are 
distinct or not. To mark its place of origin the Sind form may retain the provisional 
name of H. sincUense. Should it be eventually found that the larger and smaller 
teeth belong to more than one species the foregoing name may be restricted to the 
larger form. 
Bistrihution. — As already mentioned, all the specimens described above were 
obtained from the lower Siwaliks of Sind. 
Hyotherium, sp. 
Lower molar . — In plate XII., fig. 5, there is represented a second left lower true 
molar of a pig-like animal, which probably belongs to the present genus. The 
tooth is implanted in a fragment of the mandible, showing a part of the alveolus of 
mTF, so that there can be no doubt as to its serial position. The specimen was 
among the collection of the Asiatic Society of Bengal transferred to the Indian 
Museum, and was obtained from the Siwaliks of Perim Island. The tooth is but 
very slightly worn, and the columns are comparatively simple and distinct : the 
crown is relatively wider than the lower molars of Hyotherium soemmeringi and the 
corresponding teeth from Sind, and it is therefore probable that the present specimen 
belongs to a large species distinct from either. The lower molars of the large H. 
waterhousi are also of a more elongated type than the specimen under consideration ; 
and as the writer has been unable to identify the latter with any described form it 
appears highly probable that it indicates a new species ; although it is necessary to 
await further specimens before this can be definitely determined. 
Evolution of the Suid.® and their Allies. 
At the close of the foregoing descriptions it may be well to record a few 
observations deduced therefrom as to the probable line of evolution of the Suidce 
and their allies. The observations of M. Filhol have shown that in Hyotherium., 
which is one of the oldest forms of the family, the canines and lower incisors had 
not attained the specialized structure of those of the existing pigs ; while the 
absence of a diastema and the simple structure of the molars are also characters 
indicating a primitive type. Although, as M. Filhol suggests, it is quite probable 
that this genus is not on the direct ancestral line of the modern pigs ; yet it was 
evidently closely connected with such primitive stock. The undescribed genus 
Doliochoerus apparently indicates a form still closer to the same primitive stock. The 
remarkable agreement in cranial characters and the structure of the cutting-teeth 
existing between Hyotherium and Hippohyus indicates that the latter should in all 
1 Eilliol, op. cit., pi. VII. 
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