2 THE WORLD OF ANIMAL LIFE 



and arrangement. Until this had been done they could not even 

 be instructed in their different duties. 



We may compare a naturalist to such a general; for all the 

 many animals in the world form, as it were, a huge army. 

 His first task, then, must be to arrange these animals in some 

 way, so that he may be able, not only to study them moi'e easily 

 himself, but to inform others of his discoveries. 



How is he to do this? 



We may answer that question by remembering what the general 

 would do with his soldiers. 



Would he not look at their uniforms? Some of his men might 

 have green facings on their tunics; he would put these together 

 in one regiment. Others might have yellow facings; he would put 

 these together into another regiment; and so on. And so he would 

 arrange them in classes, as it were, according to their uniforms. 



We may do exactly the same with animals, if we consider 

 their bodily characteristics as their uniforms. That is, we may 

 put together in a " class " all those which are formed alike. 



We have not, indeed, to arrange them for ourselves at all. We 

 have only to find out Iww Nature has ari-anged them already, and 

 to put together in different classes such animals as she has m.ade 

 to resemble one another. 



Now, how would our general set to work, when he began to 

 arrange his army.-" Clearly, he would first of all separate it into 

 two or three great groups, such groups, in fact, as those which 

 we call divisions. He might, for instance, put into one division 

 all the soldiers who wore red uniforms, into a second all those 

 who wore blue, and into a third all those who wore gray or green. 

 After he had done this, he would separate these large divisions into 

 a number of brigades, and those again into regiments. And he would 

 be guided throughout by the uniforms which the soldiers wore. 



The naturalist, remembering that the bodily characteristics of 

 animals are their uniforms, proceeds upon exactly the same plan. 

 He very quickly finds that all animals may be placed in two great 

 groups. One of these contains all those that possess bones, 

 while the other includes all those that do not. And so we have, 

 as it were, the divisions in our animal army. 



