UNGULATA. 321 



accompanying diagram (fig. 182). Here will be observed the 

 gradual loss of the lateral digits, the atrophy of the ulna and 

 fibula, and the deepening of the molar teeth ; to which changes 

 must be added the increased flexibility of the neck, the reduc- 

 tion in number of the teeth, and the advancing complexity of 

 the premolars. 



The existing tapirs or Tapiridae seem to approximate most 

 closely to the earliest Eocene Perissodactyla, and afford the 

 best idea of the animals of this sub-order before they became 

 differentiated. They are adapted to live in marshes, ordinarily 

 frequenting these or dense forest in proximity to water. Their 

 teeth are short-crowned (brachyodont), each grinder with two 

 transverse ridges ; and the hinder premolars are as complex as 

 the molars. The dental series is either complete or only wants 

 one premolar. There are four digits in the manus and three in 

 the pes. The family thus characterized dates back to the 

 Lower Miocene (White River Formation) in the United States 

 of America, and apparently to the same remote period in 

 Europe. In the tapirs of this early date the premolars are 

 slightly simpler than those of the surviving genus Tapirus; 

 while Tapiravus, ranging through the Miocene and Pliocene of 

 North America, is still somewhat primitive in the same feature. 

 The typical Tapirus itself, however, is represented in Europe 

 by several fine specimens from the Lower Pliocene of Eppels- 

 heim, Hesse Darmstadt (T. priscus}, and from corresponding 

 formations in Hungary and south-eastern Austria; also by 

 remains from the Pliocene of France and Italy, and by detached 

 teeth from the Red Crag of Suffolk. It is also to be noted 

 that other teeth indistinguishable from those of Tapirus occur 

 in an Upper Tertiary (probably Pliocene) formation in China. 

 It is thus evident that during Miocene and Pliocene times 

 these animals ranged over most of the warm and temperate 

 lands of the northern hemisphere. Hence is explained the 

 remarkable distribution of the existing tapirs, which are con- 

 fined to two widely separated areas, namely, (i.) certain portions 

 of th Indo-Malayan region, and (ii.) the tropical parts of 

 America. Like the surviving Dipnoan fishes (p. 61), they are 

 an illustration of a once-dominant race nearly exterminated 

 w. 21 



