426 GENERAL BIOLOGY 



Class VI. Mammalia ( ) 



Subclass I. Prototheria ( ) 



Order 1. Monotremata ( } 



Subclass II. Eutheria ( > 



Division I. Didelphia ( ) 



Order 1. Marsupialia ( ) 



Division II. Monodelphia ( ) 



Section A. Unguiculata ( ) 



Order 1. Insectivora ( ) 



Order 2. Dermoptera ( ) 



Order 3. Chiroptera ( ) 



Order 4. Carnivora ( ) 



Order 5. Rodentia ( ) 



Order 6. Edentata ( ) 



Order 7. Pholidota ( ) 



Order 8. Tubulidentata ( ) 



Section B. Primates ( ) 



Order 9. Primates ( ) 



Section C. Ungulata ( ) 



Order 10. Artiodactyla ( ) 



Order 11. Perissodactyla ( ) 



Order 12. Proboscidea ( ) 



Order 13. Sirenia ( . ) 



Order 14. Hyracoidea ( ) 



Section D. Cetacea ( ) 



Order 15. Odontoceti ( ) 



Order 16. Mystacoceti ( ) 



BRIEF CHARACTERIZATIONS OF THE MAJOR GROUPS 



OF ANIMALS 



The principal groups of animals are given below with brief diag- 

 noses which may serve as definitions. It must be understood that the 

 characters given will often not be sufficient to distinguish all the forms 

 in a group, for there is much variation within the groups. They are in- 

 tended to give the student a general conception of the phyla, subphyla 

 and classes. 



Phylum PROTOZOA ( ). Single celled ani- 



mals without true organs or true tissues. If colonial, the cells are all 

 potentially alike. 



Class RHIZOPODA ( ). Protozoa with 



changeable protoplasmic processes (pseudopodia). Amoeba. 



