VIII.] 



THE MUSCLES. 



325 



son can be instituted between the limb-muscles of man and 

 of Fishes. Very simple muscular fasciculi represent in Fishes 

 the complex structures of higher vertebrates. 



The pectoralis major is a nearly constant muscle, but one 

 which may vary greatly as to its relative size to other 

 muscles its degree of subdivision, and the details of its 



