316 HISTORICAL PALAEONTOLOGY. 



The family of the Tapirs is represented, both in the Old 

 and New Worlds, by species of the genus Lophiodon, some of 

 which were quite diminutive in point of size, whilst others 

 attained the dimensions of a horse. Nearly allied to this 

 family, also, is the singular group of quadrupeds which Marsh 

 has described from the Miocene strata of the United States 

 under the name of Brontotheridce. These extraordinary ani- 

 mals, typified by Brontotherium (fig. 243) itself, agree with the 



Fig. 243. Skull of Brontotherium ing-ens. Miocene Tertiary, United States. 

 (After Marsh.) 



existing Tapirs of South America and the Indian Archipelago 

 in having the fore-feet four-toed, whilst the hind-feet are three- 

 toed ; and a further point of resemblance is found in the fact 

 (as shown by the form of the nasal bones) that the nose was 

 long and flexible, forming a short movable proboscis or trunk, 

 by means of which the animal was enabled to browse on 

 shrubs or trees. They differ, however, from the Tapirs, not 

 only in the apparent presence of a long tail, but also in the 

 possession of a pair of very large " horn-cores," carried upon 

 the nasal bones, indicating that the animal possessed horns of 

 a similar structure to those of the "Hollow-horned" Rumin- 

 ants (e.g., Sheep and Oxen). Brontotherium gigas is said to be 

 nearly as large as an Elephant, whilst B. ingens appears to 

 have attained dimensions still more gigantic. The well-known 

 genus Titanotkerium of the American Miocene would also 

 appear to belong to this group. 



The family of the Horses (Equidce] appears under various 

 forms in the Miocene, but the most important and best known 

 of these is Hipparion. In this genus the general conformation 

 of the skeleton is extremely similar to that of the existing 

 Horses, and the external appearance of the animal must have 

 been very much the same. The foot of Hipparion, however, 



