CLASSIFICATION OF TO-DAY 517 



with lime. The organisms with a hme skeleton are put in the class 

 called the Crustacea. All the arthropods with lime skeletons and 

 ten legs are then grouped into an order, the Decapoda. In this 

 order are found the crabs, lobsters, crayfishes, and the like. The 

 different members of the order Decapoda are then separated into 

 various genera and species. The sea-living lobster belongs to the 

 genus Homarus, while the land-living and fresh-water crayfish 

 belongs to another genus, Cambarus. There are different species 

 of lobsters in the genus Homarus. The North American lobster 

 belongs to the species americanus which is slightly different from 

 the European lobster, vulgaris. The farther down the scale of 

 classification the closer is the relationship. Species are more 

 closely related than genera and, in turn, genera are more closely 

 related than orders, etc. 

 Phylum Arthropoda. 

 Class Crustacea. 

 Order Decapoda. 

 Genus Homarus. 



Species americanus (American Lobster). 

 The Paramecium may be similarly classified. 

 Phylum Protozoa (one-celled animal). 



Class Infusoria (numerous hairlike processes used for loco- 

 motion and feeding, presence of fixed openings for 

 food ingestion and the extrusion of solid wastes). 

 Order Holotrichia — animals with cilia of equal length dis- 

 tributed over the entire body. 

 Genus Paramecium. 

 Species caudautum. 

 Using this modified Linnaeus method, let us consider a butter- 

 cup. It belongs to the great branch of phylum of the plant king- 

 dom known as the Spermatophyta. It is placed in the class Angio- 

 spermae. It is of the genus Ranunculus, and there are many 

 species. 



