WHx\T EVOLUTION IS 59 



less organs. If animals were spe- 

 cially created why should they contain 

 scores of parts that are without use 

 and that in some instances, like the 

 vermiform appendix, are positively 

 deleterious? A satisfactory answer 

 to this question has never been given. 

 From the standpoint of evolution, 

 however, rudimentary organs are 

 structures in process of disappear- 

 ance, organs that are just dropping 

 below the horizon of serviceableness. 

 Their presence in a given form in- 

 dicates that they were functional in 

 some ancestor of that form, and that 

 as evolution proceeded and the species 

 changed, it dropped this particular 

 part from the level of functional sig- 

 nificance to that of uselessness. Such 

 an explanation of the presence of these 

 organs accords completely wath what 

 is known of them from all points of 

 view. 



