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 hornj substance, resembhng 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 pi. IIS, Jig. 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- 

 pletel}'' 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 

 Cododonta and Aceratherium have been established on immature speci- 

 mens of true rhinoceros. 



Fam. 4. Pal^otherid^e. The genus Palceotherium 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 Palasotherium 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 belon2;ino; to the same g-enus. 



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 Tapir other ium 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 

 irs history goes. Its remains, all belonging to one species, were found in 

 the lead region of Illinois. It presents a peculiarity whijh 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. 



ICOXOGRAPHIC ENCYCLOPEDIA. VOL. II. 41 641 



