ORG A NIC E VOL UTION. 39 



parture from the supposed ideal type, some 

 of the other organs in the same organism 

 should tend to keep it company by doing 

 likewise. 1 



I will now briefly touch on another branch 

 of the argument from morphology — the argu- 

 ment, namely, from rudimentary structures. 



Throughout the animal and vegetable kingdoms 

 we constantly meet with organs which are the 

 dwarfed and useless representatives of organs 

 which, in other and allied kinds of animals and 

 plants, are of large size and functional utility. 

 Thus, for instance, the unborn whale has rudi- 

 mentary teeth, which are never destined to cut 

 the gums ; and we all know that our own rudi- 

 mentary tail is of no practical service. Now, 

 rudimentary organs of this kind are of such 



1 This consideration is, I believe, original. Several exceptions 

 to its validity might be adduced, but as a general principle it 

 certainly holds good. 



