4 PROTOZOA. 



Order 2. Hsemosporidia. 



Typically blood parasites of vertebrates. In 

 many forms the entire sexual period of the life- 

 cycle takes place in an intermediate host, as the 

 mosquito. (Plasmodium.) 



Class 2. Neosporidia. 



Sporulation takes place during "trophic" phase 

 of life-cycle. Sporozoites are amoebulse. 



Subclass 1. Cnidosporidia. 



Includes most of neosporidia. With bivalved 

 sporoblasts. One or more polar capsules. 



Order 1. Myxosporidia. 



Typically parasites of fishes. Free or tissue- 

 inhabiting. Spore capsule with 2 valves. 

 Usually 2 polar capsules. (Myxidium.) 



Order 2. Microsporidia. 



Minute organisms — usually 1 polar capsule. 

 (Nosema.) 



Order 3. Actinomjrxida. 



Parasites of annelids. Spores with 3 polar cap- 

 sules. (Sphseractinomyxon.) 

 Subclass 2. Sarcosporidia. 



The initial stage of the life-cycle occurs in the 

 muscle-cells of vertebrates. Spores with a sin- 

 gle polar capsule. (Sarcocystis.) 

 Subphylum 4. Infusoria. 



With motile organs in the form of cilia during 

 all or part of the life-cycle. Nucleus dimorphic 

 (macronucleus and micronucleus) . Reproduc- 

 tion is by simple transverse division or by bud- 

 ding. 



Subclass 1. Ciliata. 



With cilia throughout the life-history. 



Order 1. Holotrichida. 



The cilia are of approximately equal length and 

 equally distributed over the body. Tricho- 

 cysts are frequently present. (Prorodon, Didin- 

 ium, Paramecium.) 



Order 2. Heterotrichida. 



With a uniform covering of cilia, together with 

 an ''adoral zone" formed of cilia fused into 

 membranelles. (Spirostomum, Stentor.) 



