PROTOZOA 



9 



Order 1. Monocystidae. 

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



Order 2. Polycystidse. 

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



m 



FIG. 11. Noctiluca Miliaris (after Butschli), some- 

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

 ?)i, oral aperture ; , nucleus ; 6 and c, spores of 

 Noctiluca. 



FK;. 12. Ceratium Tripus (after 

 Biitsclili) somewhat modified. 



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

 merit) being furnished \fith hooks, etc., for adhesion ; this part is lost in time. 

 Nucleus in deutomerit. Actinoccphalus, Stylorhynchus (Fig. 

 13, A), Clcpsidriiiii. 



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 

 ,,nti-ronuc?cus and a small micronucleus (erroneously called 

 nucleolus). Reproduction by fission, conjugation frequent. 



Order 1. Holotricha. 



The whole surface is equally covered with fine cilia, often 

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



Order 2. Heterotricha. 



Possess, besides the clothing of cilia which spreads 

 equally over the whole surface, a distinctly developed zone 

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

 stomum, Stcntor (Fig. 15), Freia, Balantidium. 



Order 3. Hypotricha. 



Dorsal and ventral surfaces sharply distinguished. Ven- 

 tral surface ciliated. Chilodon, Euplotcs, Stylonychia (Fig. 14), Oxytriclia, Urostyla. 



FIG. 13. A, Stylo- 

 rhynchus longicollis, 

 after Aime Schneider. 

 ep, Epimerit ; pm, proto- 

 merit ; dm, deutomerit. 

 S, Urospora Saenuridis. 

 Conjugation of individ- 

 uals, after Kdlliker. 



