ABORTIVE ORGANS. 59 



tiatlon which causes the resemblance of the hicrher in- 

 complete, to the lower complete forms. To limit our- 

 selves to one example : it is quite incomprehensible 

 why t'f)e 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 differentiation. 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 

 nn exp^cLnation. 



