3—144 
SIWALIK SELENODONT SUINA, ETC. 
1 Jyopotamidce, in place of tlie older name Anthracotheridce : as, however, it will be 
shown in the sequel that there is a strong probability that the genus Hyopotamus will 
eventually have to be united with Anthracotherium, the older name Anthracotheridce 
will be employed here. There is a further advantage in using the term 
Anthracotheridce for the family name, because Dr. Kowalevsky seems to include 
under his family such widely-divergent forms as Anthracotherium and Anoplotherium , 
an extension of the family which, as Dr. H. Filhol, in his exhaustive memoir on the 
hyopotamids of Ronzon, 1 has shown is not advisable for general adoption. The 
Indian representatives of the family include the genera Anthracotherium and 
Hyopotamus. The second family is represented by Mixtotherium of the Quercy 
phosphorites, but there may be some doubt as to its position here. The genus 
'Dipl opus (included by Dr. Kowalevsky in the Hyopotamidce ), of which the teeth and 
skull are unknown, may form a third family of this division. The second division 
of the selenodont Suina is characterised by the crowns of the upper molars carrying 
only four columns on their masticating surface, and may be termed the tetracuspi- 
date division (Tetracuspidati.) It comprehends the families Merycopotamidce and 
Oreodontidce, both of which have Indian rejnesentatives. The third division of the 
selenodont Suina comprises the family Anoplotheridce, and may be termed the 
Anoplotherina : it 'is, however, not impossible that this division should be merged 
with the second. 
As we have already observed, the affinity of the selenodont Suina to the 
bunodont pigs is so close that there is sometimes a difficulty in assigning certain 
forms to their proper positions. On the other hand, the selenodont Suina are so 
intimately connected with the true ruminants, that here also it is frequently difficult 
to draw a satisfactory line of distinction. Thus certain of the hyopotamids pass 
insensibly into the genus Cain other ium, which is undoubtedly a true ruminant genus ; 
the oreodons are closely allied to, if not the direct progenitors of, the ancestors of 
the camel ( Procamelus , etc.); and the anoplothereres are as intimately related to the 
ruminant xiphodons. While, therefore, for the purposes of classification it is 
convenient to retain the groups Suina (with its three sub-divisions) and Ruminantia, 2 
it is highly probable that there is such a complete transition between them that they 
cannot logically be maintained. It is probable that many of the forms treated of 
here are not the true ancestors of the ruminants, but should rather be looked upon 
in the light of cousins descended from a common stock. 
Whether any or all of the animals classed here as the Suina Selenodontia were 
endowed with the power of rumination, and their internal economy modified in 
accordance with that function, is a question which cannot ever be certainly 
determined. The oreodons have, however, been termed 1 ruminating hogs,’ and 
from the close similarity of the structure of the molars of these and allied forms to 
1 “Etude des Mammiferes Fossiles de Konzon.” ‘Ann. d. Sci. Nat,’ 1881. Vol. XII., Art. No. 3, p. 89 (reprint). 
2 In former parts of this work the term Selenodonta has keen applied to the true ruminants, hut it has been thought best 
for the future to confine it to the selenodont Suina. 
