122 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Noyv. 3, 
With regard to the three true molar teeth of the upper jaw, those 
of the Cheropotamus resemble those of the Dicotyles in the general 
form of the crown, in having four chief lobes, with some minor ridges 
and tubercles: the generic distinction is indicated by difference of 
form and arrangement of these eminences: the generic distinction is 
established by the marked difference and simplification of the con- 
tiguous premolars (p 4 & p 3) mm the Cheropotamus. 
Precisely the same thing obtains in the lower jaw. The first and 
second true molars of Cheropotamus resemble those in Dicotyles in 
their four principal lobes, with minor accessory cusps, and in their 
proportionally narrower dimensions as compared with the same teeth 
in the upper jaw. The last molar of Cheropotamus also resembles 
that of Dicotyles in its fifth accessory lobe. The generic distinction 
is indicated by the same kind and degree of difference of form and 
arrangement of the minor accessories, as it is in the upper molars. 
The generic distinction is established in the lower jaw, as in the upper, 
by the sudden simplification and consequent marked difference in the 
contiguous premolars (p 4 & 3). The assertion that the deviation 
of the characters of the upper jaw and teeth of Cheropotamus de- 
scribed and figured by Cuvier (oc. cit.) from those of Dicotyles is 
so wide, and the approximation of the same characters in the lower 
jaw and teeth described and figured by me in the ‘ Geological Trans- 
actions’ to those of Dicotyles i is so close, as to make it difficult to 
admit the reference of such fossil upper and lower jaws to the same 
species of animal, is one, the nature and value of which may be left 
to the judgement of future paleontologists, without in the meanwhile 
lessening our confidence in the reference of both fossils to the genus 
Cheropotamus, or interfering with the acceptance of that genus as 
fully entitled, by the characters manifested in both the upper and 
lower jaws, to stand in the zoological catalogues according to the 
present philosophy or rules of mammalian classification. 
In truth, the penetration and sagacity of Cuvier are nowhere better 
exemplified than in his appreciation of the former existence of a new, 
and, until then, unsuspected generic form, by the feeble gleam of 
light reflected from a small fragment of a lower jaw containing but 
two or three of the least significant of the teeth. The subsequent 
discovery of the almost entire jaw of the same extinct and remarkable 
genus (Cheropotamus) confirmed the accuracy of the great Anatomist’s 
first glance. If M. de Blainville could have demonstrated that jaw to 
have belonged to a common existing genus of quadrupeds, he might 
then have plucked away one of the leaves from Cuvier’s laurels. But 
these have been too well earned and too justly awarded to render it 
necessary to expose the futility of the too frequent endeavours of the 
same kind, that detract from the merit and utility of M. de Blain- 
ville’s admirably illustrated work on Mammalian Osteology. 
The digression on the present occasion into the case of the Chero- 
potamus, and its title to a generic character, may serve however to 
show the position on which I have based my views of the nature and 
affinities of the new acquisition made by the Marchioness of Hastings 
to the series of extinct Ungulata im general, and to British Palzeonto- 
