54 



INITIATIVE IN EVOLUTION 



be found playing their ceaseless tricks on the sober normal slope 

 of hair in the skin which covers them ? If there be any region 

 approaching this I have not found it. 



The main facts of the anatomy of the horse's neck must be 

 referred to here, so that a better picture may be obtained as to 

 the powerful forces which are found in conflict during the locomotive 

 life of the animal. Fig. 3 shows the superficial layer of muscles 

 concerned in the actions of its head and neck, and the manner in 

 which adjoining muscles diverge from one another should be noted. 

 Fig. 4 gives the deepest layer of neck-muscles, the shoulder-blade 



Fig. 5. — Ligaments and tendons supporting the head and neck of 



the horse. 



having been removed, and Fig. 5 the immensely strong ligamentum 

 nuchae, of yellow elastic tissue, which extends from the base of 

 the skull to the great projecting spinous process of the lowest 

 cervical and second and third dorsal vertebrae. 



There are here indeed great forces for conflict — first a layer 

 of strong superficial muscles, second a layer of smaller muscles 

 which has not been figured, third a deep layer of muscles, and 

 fourth a powerful, widely-spread and strongly-attached mass of 



