ANIMAL PEDIGREES 239 



adductor muscle ; and almost certainly degenerate 

 in being devoid of a foot. 



Care must also be taken to avoid speaking of 

 an animal as degenerate in regard to a particular 

 organ merely because that organ is less fully 

 developed than in allied animals. An organ is not 

 degenerate unless its present possessor has it in 

 a less perfect condition than its ancestors had. A 

 man is not degenerate in the matter of the length 

 of his neck as compared with a giraffe, . nor as 

 compared with an elephant in respect of the size 

 of his front teeth, for neither elephant nor giraffe 

 enters into the pedigree of man. A man is how- 

 ever degenerate, whoever his ancestors may have 

 been, in regard to his ear muscles ; for he possesses 

 these in a rudimentary and functionless condition, 

 which can only be explained by descent from some 

 better equipped progenitor. 



We have now considered some of the more 

 important of the influences which are recognised 

 as affecting developmental history in such a way as 

 to render the recapitulation of ancestral stages less 

 complete than it might otherwise be ; which tend 

 to prevent ontogeny from correctly repeating the 

 phylogenetic history. It may at this point reason- 

 ably be asked whether there is any test by which 

 we can determine whether a given larval character 

 is or is not ancestral. Most assuredly there is no 

 one rule, no single test, that will apply in all cases ; 

 but there are certain considerations which will help 

 us, and which should be kept in view. A character 

 that is of general occurrence among the members 



