Relations of Organized Beings. 359 



The affinities in this series are seen to accumulate succes- 

 sively as we proceed from the remotest organism to the ap- 

 proximate species. The Raven and Carrion Crqw not only 

 possess that superficial resemblance of form which constitutes 

 their generic character, but they have in addition all the other 

 points of affinity which extend from them to a greater or less 

 distance into the realms of organic existence. Thus we find 

 that 



The Raven has 

 organization in common with all Organized Beings, 



a nervous system ... Animals, 



a vertebral column ... Vertebrata. 



a peculiar circulatory system ... Birds, 



perching feet ... Insessores. 



a conical beak ... Conirostres. 



the nostrils covered by feathers ... Corvidae. 



ridge of the beak arched ... Corvinae. 



an even tail ... Corvus. 



and 



a wholly black plumage ... Carrion Crow. 



It will be seen from the above example, that the whole pro- 

 cess of classification consists in observing the affinities of 

 structure in different beings, in estimating their importance, 

 and in arranging them according to that estimate. It follows 

 that a clear comprehension of affinities, as distinguished from 

 the other kinds of resemblance, is essential to the objects of 

 the scientific zoologist. 



Although affinity consists in an essential and intimate agree- 

 ment in the structure of certain organs, yet it by no means 

 implies an identity of function in those organs. The modifi- 

 cations of external form are so various that we frequently find 

 the same organ applied by different animals to purposes the 

 most remote from its normal function ; and on the other 

 hand we see very different organs applied to discharge the 

 same function. Thus, as a general proposition, it is certain 

 that the proper function of wings is flying, of legs walking, of 

 fins swimming; and yet we find examples where each of these 

 organs is applied to any other function but its own, as in the 

 case of the Bat, Seal, Ostrich, Penguin, Gurnard, and Flying 

 Fish. Hence, although it-is generally true that certain organs 

 are destined to perform certain definite functions, yet the ex- 

 ceptions are so frequent as to make us attach a minor degree 

 of importance to function, while we give the fullest weight to 

 those essential properties which form the only test of real af- 

 finity. 



