CLASSIFICA TION. 143 



The lion, tiger, leopard, puma, common cat, etc., differ 

 among themselves by minor characters, as color, size, 

 etc., and hence each is regarded as a distinct species. 

 On the other hand they all show marked resemblances 

 in number and character of teeth, and in possessing claws 

 which can be retracted into sheaths. Hence all these and 

 similar forms are united into a group or genus of cats. 

 So, too, the dog, wolves, foxes, etc., can be grouped into 

 a genus of dogs. Again cats and dogs exhibit resem- 

 blances in that they walk on the tips of the toes are 

 digitigrade while bears and raccoons walk on the sole 

 of the foot are plantigrade. Bears, cats, and dogs are 

 all flesh-eaters, and correlated with this have peculiarities 

 of structure which leads to their being united in a higher 

 group or order of carnivores. In turn carnivores, ele- 

 phants, horses, rats, whales, and man are grouped as a 

 class of mammals, the points of union being that they 

 nourish the young by milk, have bodies more or less 

 covered by hair, etc. For these and other grades of 

 similarity the following terms are used, the higher coming 

 first, the minor last. 



Kingdom 

 Phylum 

 Class 

 Order 

 Family 



/ 



Genus 

 Species 



Individual. 



Besides, other intermediate divisions, as superorders, 

 subfamilies, etc., can be interpolated in the series. 



In speaking of an animal (or a plant) two names are 



