Chap. XIY.] ANALOGICAL KESEMBLANCE8. 219 



(Antechinus) of Australia. These latter resemblances 

 may be accounted for, as it seems to me, by adaptation 

 for similarly active movements through thickets and 

 herbage, together with concealment from enemies. 



Amongst insects there are innumerable similar in- 

 stances ; thus Linnaeus, misled by external appear- 

 ances, actually classed an homopterous insect as a moth. 

 We see something of the same kind even with our 

 domestic varieties, as in the strikingly similar shape 

 of the body in the improved breeds of the Chinese and 

 common pig, which are descended from distinct species ; 

 and in the similarly thickened stems of the common and 

 specifically distinct Swedish turnip. The resemblance 

 between the greyhound and the racehorse is hardly more 

 fanciful than the analogies which have been drawn by 

 some authors between widely different animals. 



On the view of characters being of real importance 

 for classification, only in so far as they reveal descent, 

 we can clearly understand why analogical or adap- 

 tive characters, although of the utmost importance to 

 the welfare of the being, are almost valueless to the 

 systematist. For animals, belonging to two most 

 distinct lines of descent, may have become adapted to 

 similar conditions, and thus have assumed a close 

 external resemblance; but such resemblances will not 

 reveal — will rather tend to conceal their blood-relation- 

 ship. We can thus also understand the apparent 

 paradox, that the very same characters are analogical 

 when one group is compared with another, but give true 

 affinities when the members of the same group are 

 compared together: thus, the shape of the body and 

 fin-like limbs are only analogical when whales are 

 compared with fishes, being adaptations in both classes 



