516 THE MECHANICAL FUNCTIONS. 



hairs, agglutinated together into a solid mass 

 by a material which acts as a cement. This 

 fibrous structure is most distinctly seen at the 

 base of the horn, where the ends of the fibres 

 project, like those of a brush, from the surface. 

 When these horns are sawn transversely, and exa- 

 mined with a magnifying glass, a great number 

 of orifices are seen, marking the empty spaces 

 that intervene between the hairs ; and if the sec- 

 tion be made in a longitudinal direction, the same 

 spaces give rise to the appearance of parallel 

 grooves. These horns are not deciduous, like 

 those of the stag : but continue to adhere to the 

 skin, and to grow from the root, in proportion as 

 they are worn at the extremity. 



6. Solipeda. 



THE Solipeda form a natural family of quadru- 

 peds, including the Horse, the Ass, the Quagga, 

 the Zebra, &c. which are very nearly allied 

 in their conformation to the ruminant tribe. To 

 combine fleetness with strength has been the ob- 

 vious design of nature in the construction of 

 these animals. We find, accordingly, that the 

 consolidation of the bones of the foot is carried 

 still further than in the ruminant tribe ; for in 

 place of the two parallel phalanges, which are 

 in the latter articulated with the cannon bone 



