HIPPARIOH AND AHCHITHERIUM. HI 



search, however, I think that such a case is to be made 

 out in favor of the horses. The modern horse is rep- 

 resented as far back as the latter part of the Miocene 

 epoch ; but in deposits belonging to the middle of that 

 epoch its place is taken by two other genera, Hipparion 

 and Anchitherium. A species of Anchitherium was 

 referred by Cuvier to the Paleotheria. The grinding 

 teeth are in fact very similar in shape and in pattern, 

 and in the absence of any thick layer of cement, to 

 those of some species of Paleotherium. But in the 

 fact that there are only six full-sized grinders in the 

 lower jaw, the first premolar being very small; that the 

 anterior grinders are as large as or rather larger than 

 the posterior ones; that the second premolar has an 

 anterior prolongation, and that the posterior molar of 

 the lower jaw has, as Cuvier pointed out, a posterior 

 lobe of much smaller size and different form, the den- 

 tition of Anchitherium departs from the type of the 

 Paleotherium and approaches that of the horse. The 

 skeleton of Anchitherium is extremely equine. 



" In the Hipparion the teeth nearly resemble those 

 of the horse, though the crowns of the grinders are not 

 so long. Like those of the hcrse, they are abundantly 

 coated with cement. In the modern horse, finally, the 

 crowns of the grinding teeth become longer, and their 

 patterns are slightly modified." 



Alfred Eussel Wallace, F.R.G.S., &c., says ("The 

 Geographical Distribution of Animals," New York 

 edition, vol. i, p. 135) : 



" Ungulata. The animals belonging to this order 

 being usually of large size and accustomed to feed and 

 travel in herds, are liable to wholesale destruction by 

 floods, bogs, precipices, drought, or hunger. It is. for 



