DISCUSSION 181 



concerning possible morphologic homology between the 

 anterior and posterior portions of the vertebrate body. 

 Some rather fanciful argmnents were then presented 

 pro and con, but the matter has been accorded prac- 

 tically no attention in more recent times. Consideration 

 of this subject can be adequately given only by one who 

 has a very extensive knowledge of the anatomy of the lower 

 vertebrates, which the present writer has not, and his only 

 purpose in bringing up the subject is to emphasize the fact 

 that there are many interesting points for comparison 

 between the fore and hind limbs of mammals the considera- 

 tion of which one may do well to approach with an open 

 mind. It is not necessary that the theory of antero- 

 posterior sjTnmetry be accepted but merely that we note the 

 significance of the evidence of correspondence that is pre- 

 sented as regards the muscles of the fore and hind limbs. 



As expressing the relationship betw^een certain muscles of 

 either extremity, homologue is a term that seems too strong, 

 while analogue is too weak. Correspondence and counter- 

 part would perhaps be better for designating the agreement 

 of a muscle in one leg with another particular muscle of 

 the opposite extremity. 



As is well known, any such correspondence as exists is 

 between opposite muscles, as between the muscles craniad 

 of the humerus and caudad of the femur. And, broadl}^ 

 speaking, sets of muscles situated contiguously proximad and 

 distad are alternately flexors and extensors or vice versa. 

 This is morphologically due to the fact that the alternate 

 segments of a limb are inclined alternately craniad and 

 caudad. The distal extremities of the scapula and ilium^ 



' As previously mentioned, these two bones are usually considered as 

 having their morphological relationship with the trunk, but most of the 

 muscles connected with them are more intimately concerned with the limbs, 

 and as they constitute frameworks for the support of appendageous mus- 

 cles, they will be treated as segments of their respective limbs. 



