PHYLUM PROTOZOA 57 



1. Order Heliozoa. — Stiff, radial pseudopodia; frequently open- 

 work skeleton. Actinophrys, Actinosphaerium, Acanthocystis (Fig. 

 4), Clathrulina. 



2. Order Radiolaria. — Shell or spicules; central capsule; exclusively 

 marine. Acanthomctra, Acanthosphaera, Sphaerocapsa. 



b. Subclass Rhizopoda. — Pseudopodia without axial filaments; 

 typically creeping. 



3. Order Proteomyxa. — Naked; pseudopodia reticulose or filose. 

 Nuclcaria, Vampyrdla. 



4. Order Mycetozoa. — Terrestrial or semiterrestrial; plasmodium 

 formation. Arcyria, Stemonitis, Dictydium.,Cornatrichia. 



5. Order Foraminifera. — Typically myxopodia; often complex 

 calcareous shells. Globigerina, Allogromia, Polystomella, Rotalia, 

 Cyclammina (Fig. 26), Siphogenerina (Fig. 26). 



6. Order Amoebida. — Naked or simple, one-chambered shell; 

 lobopodia or filopodia. Amoeba, Endamoeba (Fig. 27), Pelomyxa, 

 Arcella, Difflugia, Centropyxis, Euglypha. 



III. Class Sporozoa. — Exclusively parasitic; reproducing by spores; 

 locomotor structures lacking in adult condition. 



a. Subclass Telosporidia. — Spore formation at close of trophic stage 

 only; intracellular parasites during part of life cycle. 



1. Order Gregarinida. — In lumen of arthropods and annelids. 

 Gregarina, Monocystis, Stenophora. 



2r~0r3er Coccidiomorpha. — Typically intracellular. Isospora, 

 Eimcria (Fig. 28), Haemogregarina, Leucocytozoon. 



b. Subclass Neosporidia. — Reproduction throughout trophic stages. 



3. Order Cnidosporidia. — Sporoblast bivalve, containing one or 

 more polar capsules; important pathogenic parasites of inverte- 

 brates and vertebrates. Myxobolus (Fig. 30), Lcptothcca (Fig. 31), 

 Myxidium, Nosema, Glugea. 



4. Order Sarcosporidia. — Muscle of vertebrates, particularly 

 mammals. Sarcocystis. 



B. Subphylum Ciliophora. — Protozoa having cilia at least in some stages. 

 rV. Class Ciliata. — Simple or compound cilia throughout vegetative 



life. 



1. Order Holotricha. — Generally with uniform body cilia; lacking 

 a specialized zone of membranelles. Prorodon, Opalina, Coleps, 

 Didinium, Dileptus, Colpoda, Colpidium, Paramecium, Lacrymaria. 



2. Order Heterotricha. — Body covered with fine cilia; left-handed 

 oral spiral of membranelles. Balantidium (Fig. 33), Stentor, Spir- 

 ostomum, Bursaria, Nyctolherus. 



3. Order Oligotricha. — General body ciliation lacking; adoral 

 cilia usually a complete ring of membranelles, the only organ of 

 locomotion. Hallcria, Strombidium, Tintinnus, Tintinnidium, 

 Entodinium, DipJodinium. 



4. Order Hypotricha. — Flattened dorsoventrally; motile organs on 

 ventral surface only; oral membranelles in left-handed spiral. 

 Kerona, Urostyla, Uroleptus, Stylonychia, Oxytricha, Euplotes. 



5. Order Peritricha. — Typically stalked; oral cilia in right-handed 



