2 PROTOZOA. 



processes about the base of the single flagellum. 

 (Mastigamceba, Trypanosoma, Euglena, Pera- 

 nema, Proterospongia.) 

 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-form- 

 ation. All are endoparasites. 

 Subclass 1. Telosporidia. 



Sporulation 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 di- 

 gestive tract or body-cavity of the host. 

 Sporulation occurs within a cyst during the free 

 period of the life-cycle. (Gregarina.) 



Order 2. Coccidiidia. 



Without a free and motile adult stage. Sporu- 

 lation occurs within a cyst during the intra- 

 cellular period of the life-cycle. (Coccidium.) 



Order 3. Hsempsporididia. 



Living chiefly in the blood-corpuscles of verte- 

 brates. In many forms the entire sexual 

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

 mediate host, as the mosquito. (Plasmodium.) 

 Subclass 2. Neosporidia. 



Sporulation takes place during the trophic 

 phase of the life-cycle. 



Order 1. Myxosporididia. 



The initial free stage occurs in the tissues or the 

 cavities of the organs of the host. The adult 

 form is amreboid. (Myxidium.) 



Order 2. Microsporidia. 



Amoeboid trophozoites. Spores very minute 

 and with but one polar capsule. 



