GENERAL PRINCIPLES OF ZOOLOGICAL CLASSIFICATION 9 



groups to any notable extent, but will have to do chiefly with 

 the smaller subdivisions. 



All organisms are classified in one of two groups called king- 

 doms, the plant kingdom and the animal kingdom or Kingdom 

 Animalia. These are naturally the largest groups, including as 

 they do all the plants on the one hand, and all the animals on 

 the other. These kingdoms are composed of several smaller 

 groups known as types ; there are a number of terms used 

 synonymously with type by different scientists, such as phylum 

 and branch. Types are divided into classes ; classes into 

 orders ; orders into families ; families into genera ; genera into 

 species ; and sometimes species into varieties. Each of these 

 groups, from the kingdom to the family inclusive, may be divided 

 into subgroups, so that we may have subkingdoms, subtypes, 

 etc., and it is sometimes necessary to make further subdivisions, 

 which are known by various names. For the elementary stu- 

 dent in zoology it is sufficient to carry the classification as far 

 as the order or at most the suborder. The names of the prin- 

 cipal divisions may be arranged as follows : — 



Kingdom. 

 Type. 



Class. 



Order. 



Family. 

 Genus. 



Species. 



Up to the year 1735 there was the greatest confusion in the 

 naming of animals. Common names were used, and naturally 

 in different localities the same animal was known by different 

 names, and different animals might be known by the same 

 name. But in the year mentioned a Swedish scientist, named 

 Linnaeus, published the first edition of a book called " Systema 

 Naturae," in which he divided all animals into classes, orders, 

 genera, and species, and adopted Greek and Latin names for 

 these various groups so that their use might be universal and 

 not confined to any one country. He devised further the bino- 

 mial nomenclature, by means of which each animal has two 

 names, consisting of the generic name followed by the specific 



