10 



PROTOZOANS. 



perfect screw in the operation. They multiply by a sim- 

 ple division (Fig. 9, c) or by budding (d, d). 



FIG. 8. Paramecium 

 bursaria, showing 

 cilia, c, contractile 

 vacuole ; ^, food. 



FlG. 9. Vorticellce. a, extended : 

 l>, coiled ; c, division ; of, d, free- 

 swimming buds. 



Works on Protozoans for further reference. 



" The Atlantic, and Depths of the Sea," Sir Wyville Thomson ; 

 Carpenter on the Microscope ; " Mind in Nature," H. J. Clark ; 

 Leidy's " Fresh- Water Rhizopods " ; Pritchard's " Infusoria " ; " Man- 

 ual of Invertebrates," T. H. Huxley ; " Challenger Reports " ; " Even- 

 ings at the Microscope," Gosse ; Thompson's " Monthly Microscopical 

 Journal"; "The Quarterly Microscopical Journal"; Bastian's "Ori- 

 gin of Lowest Organisms, and Beginnings of Life" ; " Notices of Pro- 

 tozoa," by Professor Leidy, in "Proceedings of Philadelphia Academy 

 of Natural Sciences " ; " Water turned to Blood by Red Infusoria;" in 

 "Popular Science Monthly," vol. iv, p. 202. 



