ABORTIVE ORGANS. 



59 



which causes the resemblance of the higher incomplete, 

 to the lower complete forms. To limit ourselves to one 

 example: it is quite incomprehensible why the ear-bones 

 ' of the mammal should be developed, by the circuitous 

 process of the formation of germinal fissures, if it were a 

 mere question of histological and morphological diiifer- 

 entiation. This explanation fails also with regard to the 

 whole class of the phenomena of purposeless and abortive 

 organs, and, finally, the " evolutionary type " itself as it 

 rules the groups and regulates individual development, 

 still remains without an explanation. 



