CHAPTER X 



PHYLUM PROTOZOA (Primitive Animals) 



Laboratory Exercises 



Without compound microscopes representatives of this Phy- 

 lum cannot be studied with profit in the laboratory. The 

 Amoeba is one of the most interesting of the Protozoa and serves 

 well to illustrate the simplest forms of animal life, but large 

 specimens in sufficient numbers for profitable study in an ele- 

 mentary class are usually so difficult to secure at the right time 

 that it becomes a question whether they should be depended 

 upon. Paramecium is much more available. Perhaps one of 

 the surest methods for securing Amceha is to chop up the soft 

 parts of three or four fresh-water mussels, placing the pieces, 

 together with the shells, in a large shallow basin. Allow a 

 gentle stream of water to drip into it. This keeps the water 

 slightly agitated, causes it to run over, and prevents an undue 

 accumulation of bacteria. The addition of a little of the sur- 

 face mud secured from the bottom of several streams or ponds 

 will make the success of the preparation all the surer. Amoebae 

 should appear at the surface of the mud, about the shells, 

 or at the margins of the vessel near the surface of the water. 

 Test all these places every day, and sooner or later the amoebae 

 are practically sure to be found. Paramecia^will probably 

 occur in the same preparation. Any abundant Protozoan 

 which may appear may be studied instead of Paramecium or 

 in addition to it, by means of the outline below. In order to 

 make clearer the habits of these organisms the class may well 

 take part in preparing cultures. 



190. Paramecium. — This protozoan may be obtained 

 readily by allowing fresh-water algee, with hay or leaves, to 



ISO 



