INTRODUCTION 13 



Let us trace the cat from Kingdom to Species. 



Kingdom — Animalia 

 Phylum — Ch or data 



Su b-Ph YLUM — Vertebrata 

 Class — Mammalia 

 Order — Carnivora 

 Fami l y — Felidae 

 Genus — Felis 



Species — Felis domestica. 



Metazoa. — /\nimals belonging to the Phyla above the Protozoa 

 have many cells and are called Metazoa (Gr. meta, beyond; zoow, 

 animal). Beginning as single cells, the Metazoa pass through 

 stages in which the cells are arranged in at least two layers, the 

 ectoderm and the endoderm. As adults Metazoa are made up of 

 cells arranged in unlike groups. Definitely specialized for par- 

 ticular functions, we find the cells dependent on one another, and 

 manifesting a pronounced "division of labor." 



It is customary to begin the study of zoology with types of the 

 Protozoa, the lowest of the great divisions of animals. But before 

 we take up these forms, it may be well to survey briefly the animal 

 kingdom, beginning with the highest group of Vertebrates, the 

 Mammalia, to which class we belong. 



Vertebrates 



Vertebrates belong to the most highly developed Phylum of the 

 animal kingdom, called Chordata. Members of this group include 

 five well known classes, Fishes, Amphibians, Reptiles, Birds, and 

 Mammals. All of them possess a bony axis called the backbone or 

 vertebral column. In general we find that the vertebrates are of 

 much larger size than the invertebrates, and their greater activity 

 is accompanied by special adaptations of structure. 



Phylum — Chordata. — 



Sub-Phylum — Vertebrata 



Class I. Cyclostomata 



Class II. Pisces 



Class III. Amphibia 



Class IV. Reptllia 



Class V. Aves 



Class VI. Mammalia 



