130 



UNGULATA 



ORDER VII 



Family 1 



Nasal hones, projecting freely. Dentition : 



Tapir idae Gray.^ 

 3. 1.4-3.3. 



Incisors chisel-shaped ; 



3-2.1.4-3.3." 



canines conical ; cheek teeth brachyodont. Premolars primitively simpler than 

 molars, afterwards resembling them. Upper molars with two external cusps united 

 with each other, and two straight transverse ridges uniting the two external 

 cusps with the two internal ones. Parastyle strong. Inferior molars with 

 tivo transverse crests directed either at right angles or obliquely to the longitudinal 

 axis of the croivn. Manus generally tvith four digits ; pes tridactyl. 



The tapirs include large, medium-sized and small, hoofed quadrupeds, a 

 single genus of which still exists in tropical America and in southern Asia. 



The fossil forms first appear in the 

 Lower Eocene of Europe and North 

 America, continue into the Pliocene on 

 both continents, and in the Pleistocene 

 have withdrawn to eastern Asia and 

 America. Their nearest affinities are 

 with the Rhinoceridae. 



With the exception of Colodon, 

 Lophiodon and Tapirus, all tapirs have a 

 complete dentition. As a rule, the 

 canines are separated from the cheek 

 teeth by a diastema : the latter teeth 

 are always low (brachyodont) and the 

 crown is surrounded by a basal cingulum, 

 which on the antero-external edge of 

 the teeth in the upper jaw forms a 

 more or less well -developed third pillar 

 (parastyle). The transverse ridges unit- 

 ing the internal and external tubercles 

 of the cheek teeth are nearly rectilinear 

 (ortholophodont). In the lower jaw, 

 the anterior side of the original V-shaped 

 crest is entirely obliterated ; hence, as a rule only the posterior side forms 

 the simple transverse crest. In all genera of the early Tertiary, the pre- 

 molcxrs are characterised by their simpler form, the upper jaw frequently by the 

 tritubercular structure of the molars. In existing tapirs, the reduction is 

 confined to the most anterior premolar, the other premolars having acquired 

 the appearance of true molars. In the upper jaw, four premolars are usually 

 present.; in the lower jaw, the number is four or three, the milk teeth 

 preceding them being essentially like the molars. In many genera, a 

 suppression of the most anterior premolar in the lower jaw occurs, while 



1 Deperet, Ch., Etudes sur les Lophiodons. Arch. Mus. Lyon, 1903. — Filhol, H., ^^tudes sur 

 les vertebras fossiles d'Issel. Mem. Soc. Geol. France, 1888. — Gauclry, A., La dentition des 

 aucetres des Tapirs. Bull. Soc. Geol. France, p. 315, l?!^"!.— Hatcher, J. B., Recent and 

 Fossil Tapirs. Amer. Journ. Sci., vol. i., pp. 161-189, 1896. — Maach, G., Unters. iiber 

 Lophiodon von Heidenheim. Jahresber. natnrhist. Ver. Augsburg, 1865. — Meyer, H. von, 

 Fossile Reste des G^euus Tapir. Palaeontogr., vol. xv., 1867. — Osborn, H. F., and Wortman, J. L., 

 Bull. Amer. Mus. Nat. Hist., New York, 1892.— TForiwan, J. L., and Earle, C, ibid., 1893. 



Fig. 167. 



Tapirus americanus l.ii\n. Recent. A, 

 fore-foot. B, Right hind-foot. Vs 



