KEY TO CLASSES AND ORDERS OF ANIMALS 



Phylum PROTOZOA 



I (6) Without flagella or cilia or sucking tentacles in the 

 adult condition. 2 



2(3) Body naked, or partially inclosed in a shell, movement 

 by means of pseudopodia. The pseudopodia may have 

 rigid axial filaments. Class Sarcodina, p. 6 



3(2) Body covered with a well-developed ectoplasmic 

 membrane. 4 



4(5) Free living, encysted forms which if placed in proper 

 conditions will become active and may then be 

 identified. 



5(4) Parasitic in cells, tissues, and open spaces of other 

 animals; pseudopodia and all other locomotor organs 

 lacking in the adult; shell and skeleton lacking. 



Class Sporozoa, p. 7 



6(1) Cilia or flagella or sucking tentacles present. 7 



7(8) With one or more flagella. 



Class Mastigophora (Flagellata) , p. 8 



8(7) With cilia or sucking tentacles present. 



Class Infusoria (Ciliata), p. 10 



Class SARCODINA 



1(4) Central capsule absent, marine or fresh water or 

 terrestrial. 2 



2(3) Body naked or with shell, with very changeable 

 pseudopodia which lack an axial filament (Pratt, 14; 

 W. and W., 219.) Order Rhizopoda 



6 



