2 THE THEORY OF EVOLUTION 



acquainted with this dreaded animal. A single picture 

 is there indicated with the name of 'The Wolf ' beneath 

 it, and yet it is expected that the child will recognize 

 by this single picture all wolves which it might ever 

 see in any zoological garden. 



Similar animals, but not wolves, are the Dogs, wild 

 and tame, and the Foxes. The make of the paws, the 

 toes, the entire habit and mode of life ( Garni vora) are 

 very similar ; on the other hand they differ entirely 

 in all these characters from the Sheep, Goats, etc. On 

 the strength, therefore, of the said similarities the wolf, 

 dog, fox, etc., are placed in a higher systematic unit, 

 viz. in the dog family of the Canidse. Particularly in 

 the shape of the jaw (carnivorous jaw) all dog-like animals 

 resemble the Bears, the Marten, and others ; all these 

 animals can therefore be united to a further group, 

 viz. that of the land Carnivora (Carnivora fissipedia). 

 According to the similarities which even then remain 

 between many groups, the allocation of animals to 

 higher units progresses, which naturally then become 

 ever more and more general and comprehensive. The 

 land Carnivora are united with the aquatic Carnivora 

 (Pinnipedia) to form the order of Carnivora ; then 

 with all sucking animals to form the class of Mam- 

 malia ; and finally with all animals which possess a 

 skeleton formed of jointed vertebrae, to form the 

 tribe of Vertebrates. 



It is now a question whether this graduated division, 

 which renders it possible for us to unite all animals 

 and plants into a few tribes and classes, is only the 



