392 SOL1PEDIA. 



PACHYDERMATA. SOUP EDI A. 



Fig. 151. Fig. 152. 



1st upper molar, nat. size, Equus 1st upper molar, nat. size, Equus 

 oabattus, plicidens, Orestou. 



FOSSIL HORSE, WITH THE ENAMEL-FOLDS OP THE MOLAR 

 TEETH PLICATED. (Equus plicidens.) 



AMONGST the numerous teeth of a species of Equus, as 

 large as a horse fourteen hands and a half high, collected 

 from the Oreston cavernous fissures, I have found specimens 

 clearly indicating two distinct species, so far as specific 

 differences may be founded on well-marked modifications of 

 the teeth. 



One of these, like the ordinary Equus fossilis of the drift 

 and pleistocene formations, differs from the existing Equus 

 caballus by the minor transverse diameter of the molar 

 teeth, and is noticed in the preceding section ; the other, 

 in the more complex and elegant plication of the enamel, 

 and in the bilobed posterior termination of the grinding 

 surface of the last upper molar, more closely approximates 

 to the extinct Horse of the miocene period, which M. H. 

 v. Meyer has characterised under the name of the Equus 

 caballus primigenius.* The Oreston remains differ, how- 



* ' Nova Acta Acad. Nat. Curios.' torn. xvi. p. 448. 



