12 THE PROTOZOA 



are Amoeba (Fig. 2), Difflugia (Fig. 16), Actinosphcerium 

 (Fig. 3), etc. 



CLASS II., MASTIGOPHORA.* Protozoa in which the organs of 

 locomotion and food-capture in the adult are flagella, slender fila- 

 ments which are capable of performing active whip-like, lashing 

 movements. The body -protoplasm may be naked or corticate. 

 Examples are Euglena (Fig. 4), Trichomonas (Fig. 5), Trypanosoma 

 (Fig. 6), etc. 



CLASS III., SPOROZOA. Protozoa occurring always as parasites 

 of other organisms, and without definite organs for locomotion or 

 ingestion of food in the adult condition. The reproduction takes 

 place, typically, by formation of resistant seed -like bodies, termed 

 spores, containing one or more minute germs, termed sporozoites. 

 Examples are Gregarina (Fig. 7), Coccidium (Fig. 152), the malarial 

 parasites (Fig. 156), etc. 



CLASS IV., LNTUSORIA. Protozoa in which the organs of loco- 

 motion and food-capture are cilia, small vibratile filaments dis- 

 tinguished from flagella by their smaller size, by differences in 

 their mode of movement, and by being present usually, in primitive 

 forms at least, in great numbers like a fine fur over the whole or 

 a part of the surface of the body. The cilia may be present through- 

 out life (subclass Ciliata), or only in the early stages of the life- 

 history (subclass Acinetaria). The body -protoplasm is always cor- 

 ticate. Examples are Stentor (Fig. 8), Nyctotherus (Fig. 9), Acineta 

 (Fig. 10), etc. 



Bibliography. For a list of general works on Protozoa, see p. 476. 

 * Derived from the Greek pd(TTi, a whip, equivalent to the Latin flagellum. 



