226 REPORT—1843. 
posterior half of the left ramus of the lower jaw with the three true molar 
teeth: it was found in the lowest bed of the freshwater marl at Binstead. 
Molar teeth of the same species of Dichobunes have been obtained by Mr. 
Flower from Hordwell Cliff, associated with the Palgotherium crassum, and 
with other lower organized Vertebrate fossils of the Eocene period, as Cro- 
codilus Spenceri, Trionyx, Paleophis, Lepidosteus, &c. 
Genus Charopotamus. 
Cuvier had recognized amongst the fossil fragments extracted from the 
gypsum at Montmartre, indications of extinet genera different from the Pa- 
leotheria and Anoplotheria, and to one of the rarest and least satisfactorily 
represented of these he gave the name of Cheropotamus. The fossil to be 
here noticed not only extends, by its association with the Palotheria and 
Anoplotheria, the analogies of the eocene marls of the Isle of Wight with 
the gypsum beds at Paris, but affords additional information of the osteology 
and dentition of the extinct genus, which is essential to the determination of 
its exact affinities. The details of the comparisons illustrating this part of 
the history of the Chceropotamus are given in my paper in the Geolagical 
Transactions* ; they show that the extinct Chceeropotamus constituted one of 
the numerous examples in paleontology of lost links in the chain of animated 
nature, tending in the present case to connect the Pachydermata through the 
Hog-tribe with the plantigrade Carnivora. 
The fossil in question is the right ramus of the lower jaw, with all the 
teeth in place except the second premolar and the incisors. It was discovered 
by the Rev. D. Fox in the Seafield quarry, near Ryde, Isle of Wight. 
Genus Hyracotherium. 
The freshwater eocene marls of the Isle of Wight are much richer in mam- 
malian remains than the contemporaneous formation called the London clay; 
here, however, one genus, Lophiodon, has been found which exists in the 
eocene gypsum in France, the remains of which also occur in the eocene 
marls of the Isle of Wight; and the interesting fossil to be described in the 
present section, although it indicates a genus not, hitherto, found in the older 
tertiary beds on the continent, demonstrates the extinct quadruped of which 
it formed part to have been as distinct generically, as the Anoplotherium or 
Paleotherium, from any living Mammalia, and to have had the nearest affinity 
to the Cheropotamus. 
The fossil in question consists of a mutilated cranium about the size of that 
of a hare, containing the molar teeth of the upper jaw nearly perfect and the 
sockets of the canines. It was discovered in the London clay forming the 
cliffs at Studd Hill, about a mile to the west of Herne Bay, by William 
Richardson, Esq., who kindly gave me the opportunity and permission of 
describing it. 
The molars are seven in number on each side, and resemble more nearly 
those of the Cheeropotamus than the molars of any other known genus of ex- 
isting or extinct Mammalia. They consist of four premolars and three true 
molars. 
The first and second premolars, counting from before backwards, have 
simple subcompressed crowns, surmounted by a single median conical cusp 
with a small anterior and posterior tubercle at the outer side, and a ridge 
along the inner side of its base: they are separated from each other by an 
interspace nearly equal to the antero-posterior diameter of the first premolar, 
which measures two lines and a half. The second and the remaining molars 
* Geol. Trans. Second Series, vol, vi. p. 41. 
