INTRODUCTION. 



13 



Particular names, which are, usually, descriptive of some pecu- 

 liarity on which the classification is based, have been given to 

 each of the divisions and subdivisions of the Animal Kingdom. 

 Thus, the first subkingdom is called the Vertebrate, as it com- 

 prises all animals which have a vertebral column or backbone ; 

 the second subkingdom is termed the Articulate, since it con- 

 tains those having a jointed body and limbs. The names and 

 a general description of the six subkingdoms are given in the 

 following table : 



* The Echinoderms and the Coelenterates were formerly assigned to a single 

 Subkingdom RADIATES and are often called by that name. 



