1847.] OWEN ON EXTINCT ANTHRACOTHERIOID QUADRUPEDS. 125 
bear in mind that in certain extinct Ungulates the last permanent 
premolar or the first permanent true molar may also have a third lobe 
or transverse division of crown when the molars succeeding them 
have but two such lobes or transverse divisions. From these con- - 
siderations I am induced to regard the tripartite (six-lobed) tooth as 
the first permanent premolar in the Anthracotherioid (An. szlistrense) 
figured in the Geol. Trans., 2nd Series, vol. ii. pl. 45. figs. 2 & 3, and. 
the bipartite (four-lobed) contiguous tooth as the first true molar, in 
which case the Indian fossil represented by those teeth would be much 
more nearly allied to Dichodon than to Anthracothertum: the lower 
molars (figs. 1, 13, mm the same plate) resemble, like those in Dicho- 
don, the lower molars of Dichobunes more than they do these of the 
typical Anthracotherium. 
Lady Hastings, in the letter above-cited, relative to her discovery 
of the fossil jaw and teeth of the Hyopotamus, asks, ‘‘ Are they Cory- 
phodon?”’ And, in fact, the high and sharp-pointed lobes of the 
teeth might well suggest a probable relationship to the rare British 
eocene Pachyderm, described on account of its multi-cuspidate molars 
under that name*. However, the last molar of Hyopotamus, though 
contracting posteriorly, like that of Coryphodon, presents a distinct 
third cuspidate division in place of a mere basal talon, and the two 
points of the anterior division of the crown are divided by a deeper 
and more decided cleft than in Coryphodon. M. de Blainville, it is 
true, unwilling to admit the force of the evidence of a new genus 
when manifested by a small portion only of the dentition of an extinct 
species, supports his charge of temerity against me by suggesting that 
the tooth which I have described as the last molar may be the first 
molar in the fragment of fossil jaw figured in my work. But, were 
this the case, it would still remain to be shown what recent or fossil 
species or genus of mammals has an anterior molar tooth like that 
described and figured in pp. 299-305, cuts 103, 104, 107, of the 
‘ British Fossil Mammalia.” M. de Blainville suggests that it may 
belong to some small species of Dinotherium+. Now what the rela- 
tion may be between the fossil tooth of Coryphodon and that of a 
hypothetical and unknown species of Dinotherium, cannot of course 
be determined ; but with respect to the known species of Dinotherium, 
the anterior molar of these has neither the posterior talon, nor the 
posterior bicuspid transverse ridge, nor the complex tricuspid anterior 
lobe with an anterior talon, which would be requisite to support M. 
de Blainville’s idea of the nature of the tooth of the Coryphodon. 
For with respect to the ‘some one or other’ of the anterior teeth of 
a Dinotherium, it could only be with the foremost that this tooth 
of the Coryphodon could be compared, on the hypothesis that it be- 
longs to the fore-part of the series; because the portion.of jaw pre- 
served with it demonstrates it to have been the terminal tooth of the 
molar series. Now against the supposition that it has terminated the 
series anteriorly there is the swelling out of the jaw on its exterior 
* British Fossil Mammalia, p. 299. 
+ “‘ A’ moins que ce ne soit quelqu’une des dents antérieures d’un petit Dino- 
therium.” (J. c. p. 109.) 
