PROTOZOA 



Order 1. Monocystidse. 

 Body simple. Monocystis (in the Earthworm), Urospora (Fig. 13, B). 



Order 2. Polycystidse. 

 Body divided by a partition wall into anterior (protomerit) and posterior (deuto- 



f 



Pig. 11.— NootiluoaMlllaris(atterButsolili), some- 

 what altered, ig, Band-like flagellum ; /, flagellum ; 

 m, oral aperture ; n, nucleus ; h and c, spores of 

 Noctiluca. 



Fig. 12.— Ceratium Tripus (after 

 Butschli) somewhat modified. 



merit) divisions. The protomerit often again divides, the anterior division (epi- 

 merit) heing furnished with hooks, etc., for adhesion ; this part is lost in time. 

 Nucleus in deutomerit. Actinocephahts, SiylorhyncAus (Fig. 

 13, A), Clepsidrina. 



Class V. Infusoria (Ciliata). 



Unicellular Protozoa, rarely united in simple colonies, 

 with cilia or cilia-like processes for locomotion and alimenta- 

 tion. Generally with contractile vacuoles, oral and anal 

 apertures. With double nucleus : a variously formed large 

 macronucleus and a small micronueleus (erroneously called 

 nucleolus). Reproduction by fission, conjugation frequent. 



Order 1. Holotricha. 



The whole surface is equally covered with fine cilia, often 

 arranged in rows. Paramceciuin (Fig. 20, p. 17), Trachelius. 



Order 2. Heterotricha. 



Possess, besides the clothing of cilia which spreads Fig. is.— a, Stylo- 



rhynolius longicollis, 

 after Aim^ Sclineider. 

 ep, Epimerit ; pm, proto- 

 merit ; dm, deutomerit. 

 B, TJrospora Sasnurldis. 

 Conjugation of individ- 

 uals, after Edlliker. 



equally over the whole surface, a distinctly developed zone 

 of bristle- or stylet-shaped cilia near the mouth. Spiro- 

 stoimim, Stentor (Fig. 15), Freia, Balantidium. 



Order 3. Hypotricha. 



Dorsal and ventral surfaces sharply distinguished. Ven- 

 tral surface ciliated. Chilodon, Eicplotes, Stylonychia (Fig. 14), Oxytricha, Urostyla. 



