MAMMALIA. 437 
by the horn-like processes which it exhibits on the nose, and to which its 
name refers. The horn or horns (there being one or two present) consist 
of a fibrous and horny substance, resembling agglutinated hairs, and adhering 
to the skin. Each foot is divided into three toes. There are four incisors 
above and four below, two being very small or completely wanting, and 
seven molars on each side. No canines. The rhinoceros of India (R. 
indicus) is represented on pil. 118, fig. 1, and will give an idea of its clumsy 
appearance. ‘The African species is provided with two horns on the snout. 
Rhinoceroses have been much more numerous during the tertiary epoch than 
in our days, and have inhabited countries from which they are now com- 
pletely excluded. Their fossil remains have been found from the north of 
Europe to the south, in France, Italy, England, and especially in Germany. 
Ten to eleven extinct species are already on record. Some of them are 
relatively small sized. Several species are known from the eocene of the 
Upper Missouri. It is perhaps worth mentioning here that the genera 
Celodonta and Aceratherium have been established on immature speci- 
mens of true rhincceros. 
Fam. 4. Parzorureripa.. The genus Paleotherium is without living 
representatives, but its outlines have been restored from the study of com- 
plete skeletons. The nasal bones resemble somewhat those of the tapir, 
indicating clearly that Paleeotherium had similar forms and a small flexible 
proboscis. The fore and hind limbs have three hoofed toes. Upwards of 
twelve species are described as having been found in the old world. The 
western tertiary deposits of America have also yielded jaws and other frag- 
ments belonging to the same genus. 
The genus Lophiodon comes nearer Tapirus, from which it differs in the 
structure of the molars, the relative number and proportion of the folds of 
enamel. A dozen species of this genus have already been made known 
by fragments more or less numerous. These remains were found chiefly 
in France and Germany, where the animals referred to lived mostly during 
the meiocene period. 
The genus Tapirotherium was founded upon one species of Lophiodon. 
The genus Listriodon is distinguished from Lophiodon by the structure of 
the teeth. The genus Coryphodon, in the actual state of our knowledge, is 
not certainly distinct from Lophiodon. The affinities of the genus Tapiro- 
porcus are still to be investigated, as they might prove, perhaps, relation- 
ship with the Suiline family instead of the present one. 
The genus Platygonus is American, as far at least as our knowledge of 
its history goes. Its remains, all belonging to one species, were found in 
the lead region of Illinois. It presents a peculiarity which is only observed 
in Hippopotamus, although to a much less degree, consisting in the dilata- 
tion of the angle of the lower jaw into a large and broad expansion, 
concave outwards. The superior canines are compressed, acute, and 
slightly curved, directed forwards and downwards so as to be entirely con- 
cealed by the lips as in Tapirus and Lophiodon. We have, therefore, here 
a type which combines the characters of several quite distinct genera, 
although not yet fully understood. 
ICONOGRAFHIC ENCYCLOPADIA.—VOL. II. 4] 641 
