194 VIGNETTES FROM NATURE. 



part passn with this development of a special 

 form of hoof adapted to the free roaming- 

 existence of the horse tribe there has gone on 

 a constant increase in the relative size and 

 weight of the brain. Our comparative 

 anatomists as a rule naturally attach most 

 importance to the development of the bony 

 skeleton, and especially of those parts which 

 are most characteristic of families and genera. 

 Psychology is a subject that interests them , 

 comparatively little. Hence we lay-readers 

 are apt to get rather surfeited with descrip- 

 tions of changes in the supra-condyloid 

 foramen or the lateral ethmoid, about which 

 the world at large is culpably indifferent ; 

 while we hear hardly anything as to the 

 evidences of mental development, about 

 which the world at large feels a much more 

 genuine interest. As a matter of fact, in the 

 pedigree of the horse and the donkey there 

 is abundant proof of such progress. The 

 brain of the evolving horse tribe goes on in- 

 creasing (as we judge from the skulls) with 



