84 RUMINATING ANIMALS. 



considers them as one of the most natural and test 

 determined groups among the Mammalia. The ex- 

 ternal characters may be placed here, to indicate the 

 order : " Incisive teeth only in the lower jaw, where 

 they are generally eight in number. In the upper 

 jaw, instead of teeth, there is a callous pad. Be- 

 tween the ipojsivp t*>eth and the grin'l r there is 

 generally an empty space ; but in a tew genera, as 

 the Camels and Musks, this is partly supplied by 

 one or two canine teeth sometimes assuming the 

 form of tusks. The grinders are almost always six 

 on each side of each jaw, and have their crown or 

 surface marked with two double crosses, of which 

 the convexity is turned inwards in the upper teeth, 

 and outwards in the lower. The four feet are ter- 

 minated by two toes, defended by two hoofs, which 

 are applied to each other with a flat surface, so as 

 to resemble a single hoof which has been cleft. Be- 

 hind these hoofs there are sometimes two small or 

 rudimentary hoofs, which are the only appearances of 

 lateral toes: the two metacarpal and metatarsal bones 

 are united in one, which receives the name of ' Can- 

 non bone.'* The head is most frequently furnished 

 with horns, sometimes common to both sexes, some- 

 times confined to the male only, dechluous, or with 

 a bony core. The hair is sometimes crisp, thick, 

 and slightly curled, or long, and bearing the title of 



* Tn some species there are traces of lateral metatar- 

 Jal and metacarpal bones. 



