2 



PROTOZOA. 



one or more flagella. The members of one order 

 (Choanoflagellidia) have one or more collar-like 

 processes about the base of the single flagellum. 

 (Mastigamceba, Proterospongia, Euglena, Pera- 

 nema.) 



Subclass 2. Dinoflagellidia. 



Usually with two flagella, one encircling and 

 the other directed away from the body. (Peri- 

 dinium, Ceratium.) 



Subclass 3. Cystoflagellidia. 



With two flagella, one of which is modified into 

 a " tentacle," while the other is short and con- 

 tained within the gullet. (Noctiluca.) 

 CLASS 3. Sporozoa. 



Without flagella or cilia in the adult period of 

 the life-cycle. Reproduction is by spore-forma- 

 tion. All are endoparasites. 



Subclass 1. Telosporidia. 



Reproductive phase of the life-cycle is distinct 

 from, and follows the trophic phase. 

 Order 1. Gregarinida. 



The young stages are intracellular parasites, while 

 the adults are free and motile in the digestive 

 tract or body-cavity of the host. Sporulation 

 occurs within a cyst during the free period of the 

 life-cycle. (Gregarina.) 

 Order 2. Coccidiida. 



Without a free and motile adult stage. Sporula- 

 tion occurs within a cyst, during the intracellular 

 period of the life-cycle. (Coccidium.) 

 Order 3. Haemosporidiida. 



Living chiefly in the blood-corpuscles of verte- 

 brates. In many forms the entire sexual 

 period of the life-cycle takes place in an in- 

 termediate host, as the mosquito. (Laverania 

 malaria^.) 



Subclass 2. Neosporidia. 



Reproduction takes place during the trophic 

 phase of the life-cycle. 

 Order 1. Myxosporidiida. 



The initial free stfigo occurs in the tissues or the 

 cavities of the or-rans of the host. The adult form 

 is amoeboid. (Myxidium.) 



