EDMONDSON — PROTOZOA OF IOWA. 



27 



It has been my privilege to observe the process of the forma- 

 tion of the stem by which Clathrulina tlcgans attaches itself to 

 some support, usually aquatic plants. A naked individual, the 

 result of recent fission, came under observation, swimming freely 

 for a time; then^ a cone-shaped outpushing of the protoplasm 

 took place on one side, the protoplasm adhering to a particle of 

 plant tissue, and a stem began to develop. After three hours 

 the stem had reached its normal length, which is about one and 

 one-half times the diameter of the body. 



Figure 40 illustrates a normal adult individual. Fig. 42 rep- 

 resents an earlier phase in the animal's life. 



Found in fresh water among aquatic plants. 



TABLE OF CLASSIFICATION. 



Class, MASTIGOPHORA. 



Small forms of Protozoa provided with one or more flagella. 

 Often forming colonies. 



Sub-class, FIvAGKLLIDIA. 



Naked or enclosed by a membrane. One or more flagella aris- 

 ing from or near the anterior end. 



Sub-class, DINOFLAGELIJDIA. 



Often provided with shells and usually having at least two fur- 

 rows, one transverse and one vertical. Flagella usually two, one 

 directed around the body and one away from it. Mostly salt 

 water forms. 



Sub-class, CYSTOFLAGELLIDIA. 



Flagellates of large size, enclosed by a firm membrane. Salt 

 water forms. No further classification of this group is given in 

 this paper. 



Orders of FEAGEELIDIA. 



MONADIDA. 



Small forms, sometimes amoeboid, with no distinct mouth. 

 Flagella one or two. 



CHOANOFLAGEEIvIDA. 



Flagellum single, about the base of which is developed a mem- 

 branous collar. Often forming colonies. 



