CAVE-HORSE. 13 



touches the ground; the cleft being narrow and deep. A still 

 greater development of the hind part of the frog occurs in the Ass 

 {E. asinus). In the extinct South American Onohippidium the 

 frog is somewhat intermediate between the Horse and the Ass 

 type, being grooved and not projecting behind the case of the 

 hoof, but being of considerable breadth and tliickness. In the 

 Bonte-Quagga or Burchell's Zebra (Equus hurchelli) of South 

 and Eastern Africa the medium -sized and slightly cleft frog is 

 deeply sunk in the hoof, behind which it projects to a small 

 degree; not touching the ground, except when the hoof is 

 much worn. 



Characteristics Coming to the characteristics of the Horse itself, 

 of tlie as typified by the domesticated Scandinavian 



Horse. breed, the species is distinguished by the tail 



being abundantly covered with long hair up to the root and the 

 general presence of bare callosities or, " chestnuts,''^ on the inner 

 side of both pairs of limbs. The mane, which has a forelock on 

 ihe forehead, is long and pendant, the ears are relatively short, 

 the head small, the limbs long, and the hoofs large and broad, 

 especially the front pair, w^hich considerably exceed the hind ones 

 in this respect. Normally there are no distinct colour-markings ; 

 although dark bars are not unfrequently seen on the legs, and 

 more rarely on the shoulders, of dun-coloured individuals. 



This definition requires, however, some amount of modification 

 when the wild representatives of the species are taken into con- 

 sideration. The following main types or races of the Horse may 

 be recognized, of which the first is : — 



_, p The Cave Horse, Equus cabaUus spelceus, a race typified 



by bones and teeth from the cavern of Bruniquel, Tarn- 

 et-Garonne, France, described by Sir R. Owen in the 

 Philosophical Transactions of the Royal Society for 1869, and 

 exhibited in the Geological Department. It was then supposed to 

 indicate an animal of about 13^ hands in height, but the relatively 

 large size of the cheek-teeth of the next race indicates that it 

 was probably much smaller. Prehistoric sketches from the Cave 

 of La Madelaine, in the Dordogne, south of France (fig. 12), 

 show that this race was practically identical with the living 

 Wild Horse of Mongolia, having the same relatively large 



