XI PHENOMENA OF ORGANIC NATURE 325 



fore-leg of the horse or the dog, or the ape or 

 mail ; and here you will notice a very curious 

 thing, the hinder limbs are absent. Now, let 

 us make another jump. Let us go to the codfish : 

 here you see is the forearm, in this large pectoral fin 

 carrying your mind s eye onward from the flapper 

 of the porpoise. And here you have the hinder 

 limbs restored in the shape of these ventral fins. 

 If I were to make a transverse section of this, I 

 should find just the same organs that we have 

 before noticed. So that, you see, there comes out 

 this strange conclusion as the result of our 

 investigations, that the horse, when examined 

 and compared with other animals, is found by no 

 means to stand alone in Nature ; but that there 

 are an enormous number of other creatures which 

 have backbones, ribs, and legs, and other parts 

 arranged in the same general manner, and in 

 all their formation exhibiting the same broad 

 peculiarities. 



I am sure that you cannot have followed me 

 even in this extremely elementary exposition of 

 the structural relations of animals, without seeing 

 what I have been driving at all through, which is, 

 to show you that, step by step, naturalists have 

 come to the idea of a unity of plan, or conformity 

 of construction, among animals which appeared at 

 first sight to be extremely dissimilar. 



And here you have evidence of such a unity of 

 plan among all the animals which have backbones. 



