228 THE ORIGIN OF SPECIES 



gonj^s ami whales, and between these two orders of mam- 

 mals ami fishes, are analogical. So is the resemblance 

 between a mouse and a shrewmouse (Sorex), which belong 

 to different orders; and the still closer resemblance, in- 

 sisted on by Mr. Mivart, between the mouse and a small 

 marsupial animal (Antechinus) of Australia. These latter 

 resemblances may be accounted for, as it seems to me, 

 by adaptation for similarly active movements through 

 thickets and herbiige, together with concealment from 

 enemies. 



Among insects there are innumerable similar instances; 

 thus Linnaeus, misled by external appearances, actually 

 classed a homopterous insect as a moth. We see some- 

 thing 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 analo- 

 gies 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 the}^ reveal descent, 

 we can clearly understand why analogical or adaptive 

 characters, although of the utmost importance to the 

 welfare of the being, are almost valueless to the syste- 

 matist. For animals, belonging to two most distinct lines 

 of descent, may have become adapted to similar condi- 

 tions, and thus have assumed a close external resem- 

 blance; but such resemblances will not reveal — will 

 rather tend to conceal their blood -relationship. We can 



