320 



ORDERS OF MAMMALIA. 



fed in all except the Tapirs and Brontotheridce. The dorso- 

 lumhar vertebrce are never less than twenty-two in number. The 

 femur has a third troehanter. .The horns, if p)'^^<^sent, are not 

 paired {except in the extinct genus Dicer atheriuni). Usually 

 there is only one horn, hut if there are tvjo, these are placed in 

 the middle line of the head, one behind the other. In neither 

 case are the horns ever supported by bony horn-cores. The 

 stomach is simple, and is not divided into sf-vercd compxirtments ; 

 and there is a large and capacious ccecum. 



The tyj)ical state of matters in the Perissodactyles is that 

 the third digit of the foot should be pre-eminently and sym- 

 metrically developed, and should either exist alone {Equus), 

 or should be flanked by the second and fourth digits, the 



Fig. 624.— Feet of Ungulata. a, Fore-foot of Tapir(rf'i)in(.s Malayanus) ; B, Perissodactyle 

 fore-foot of Rhinoceros Sumatrensis ; c, Artiodactyle foot of Pig (Svs scrofa). The figures indi- 

 cate which of the normal five digits are present in each foot. (After Flower.) 



size and length of these varying in different cases, but always 

 falling short of the dimensions of the central digit {Rhin- 

 oceros, fig. 624, b). No living Perissodactyle Ungulate pos- 

 sesses the inner or first digit on either fore or hind feet. The ' 

 Tapirs, however, have a small fifth digit (fig. 624, a) devel- 

 oped on the fore-feet, the inner digit of which is still wanting ; 

 tbe extinct Oroliiiipus has similarly the fifth digit de^'eloped 



