54 PARALLELISM IN DEVELOPMENT. 



different metliods, vet wlien we find precisely similar 

 structural modifications in different groups of animals 

 which clearly cannot be traced to a common ancestry, and 

 for which equally efficient substitutes could be readily 

 suggested, we are fain to confess that the ordinarily 

 accepted exjslanations of evolution ajipear to us altogether 

 inadequate. Patting this aspect of the matter aside, our 

 readers will, however, see from the imperfect sketch given 

 above, what an imjjortant factor in evolution parallel 

 development really is, and how largely it is likely in the 

 future to modify our present views as to the mutual 

 relationships of animated nature. 



