ANALOGICAL RESEMBLANCES 463 



tion for similarly active movements through thickets and 

 herbage, together v^^ith concealment from enemies. 



Amongst insects there are innumerable similar instances; 

 thus Linnaeus, misled by external appearances, 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 re- 

 semblance 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 adaptive 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-relationship. 

 We can thus also understand the apparent paradox, that the 

 very same characters are analogical when one group is com- 

 pared 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 

 for swimming through the water; but between the several 

 members of the whale family, the shape of the body and the 

 fin-like limbs offer characters exhibiting true affinity: for as 

 these parts are so nearly similar throughout the whole fam- 

 ily, we cannot doubt that they have been inherited from a 

 common ancestor. So it is with fishes. 



Numerous cases could be given of striking resemblances 

 in quite distinct beings between single parts or organs, which 

 have been adapted for the same functions. A good instance 

 is afforded by the close resemblance of the jaws of the dog 

 and Tasmanian wolf or Thylacinus,— animals which are 

 widely sundered in the natural system. But this resemblance 



