3cS EXPERIMENTAL EVOLUTION LECT. 



is exceptionally met with in man, which does not 

 represent the normal condition in apes or in other 

 animals, and this is a fact of great importance to the 

 evolutionist. But it sorely tries the feelings of the 

 creationist, who cannot explain the case, who cannot 

 give any satisfactory reason for the presence, in that 

 specially created creature, man, of muscles which 

 typically belong to some other mammal, ape, bear, or 

 hog, also specially created. 



A third argument for evolution is offered by the 

 facts of morphology. Morphology shows the unity 

 of plan of quite different organs, as for instance, the 

 arm of man, the fore-paw of the lion, the wing of the 

 bat, the fin of the whale, and the wing of the bird ; 

 it shows that they arc all made up of the same ele- 

 ments which are more or less modified in each case 

 according to what is required from them. The same 

 may be said of the numerous homologous organs in 

 any large group : as for instance the mouth-parts of 

 insects, which, although very different in their anatomy 

 and also in their function, when considered in the dif- 

 ferent orders of insects, are easily seen to be identical 

 fundamentally, whether the mouth is used for biting, 

 for sucking, or for other purposes. Other organs in 

 the same group, and sometimes in very large sub- 

 divisions of the animal kingdom, admit of being 

 morphologically compared, and in many cases we 



