CLASSIFICATION 85 



base for a classificatory scheme. At first, and with the older genera- 

 tion, it was bill and claw ; then came a period of bones ; later the 

 muscles were held to be all-important ; at present the fashion is in 

 favour of taking all characters into consideration, which is clearly a 

 more reasonable way of looking at the matter. The reason for the 

 divergences of opinion which implies great difficulty in the subject 

 is that birds are so modern a race. They are now at their heyday 

 of development. By-and-by, when gaps appear in the now serried 

 ranks, classification will be an easier matter ; for classification, after 

 all, is an artificial, unnatural sort of thing, if we believe in a gradual 

 modification of species out of pre-existing species. It is not too 

 much to say that, the more perfect our scheme of classification, the 

 greater our ignorance of the group classified. If the only birds 

 known to science were a Hornbill, a Duck, and a Crow, together with 

 a few of the immediate allies of each, we could easily sort them. 

 But there are so many intermediate forms which absolutely decline 

 to fit accurately into any system. Then the would-be systematist 

 has to distinguish between those characters which imply a deep- 

 seated relationship and those which are only due to similar needs. 

 The aim of classification is, of course, to indicate real relationship, 

 not merely to pigeon-hole in a convenient way. Heal relationship 

 is often masked by superficial differences. For instance, the 

 common blindworm of our hedgerows is not, as might be thought, 

 a snake, but a lizard ; it appears to be unlike the lizard in having no 

 legs, and to be so far a snake. Indeed, the terror inspired by this 

 peaceful reptile must stand it in good stead with any except human 

 foes. But its whole anatomy is built upon the lizard, and not upon 

 the snake, plan. We disregard, therefore, in a scheme of classifica- 

 tion the likeness to a snake, remembering that in Nature, as in 

 morals, appearances are apt to be deceptive. The owls, among 

 birds, are believed by many to offer an instance of the same kind of 

 deception. By all the older systematists, and by many of the more 

 modern, they are placed with the hawks in one group. No doubt 

 the owls bear a certain likeness to the hawks. They have formid- 

 able claws and a hooked and powerful beak ; they kill their prey ; 

 and only differ superficially in that they love the darkness, while the 

 hawks hunt by day. Now, in certain details of anatomy, particularly 

 in the windpipe and the muscles, the owls are much more like that 

 division of birds which includes the goatsuckers. The mention of 

 this latter family brings us face to face with another difficulty. If 

 the superficial likeness of the owls to the hawks is to be distrusted, 



