AMOEBA PROTEUS. 5 



Kent: Manual of the Infusoria, 1881. 



Lankester: Treatise on Zoology. 1. Protozoa. 



Leidy: Fresh Water Rhizopods of North America, 1879. 



Maupas: Studies on Infusoria, in Arch. Zool. Exp. et Gen., 1883, 1888, and 



1889. 



Minchin: Protozoa, 1912. 

 Prowazek: Einfiihrung in die Physiologic der Einzellgen (Protozoen), 1910. 



: Taschenbuch der Mikroskopischen der Protistenuntersuchen, 1907. 



Stokes : Contribution Toward a History of the Fresh Water Infusoria of the 



United States. Jour. Trenton Nat. Hist. Soc., 1, 1888. 

 Whipple: Microscopy of Drinking Water, 3d ed., 1914. 

 Woodruff: Observations on the Origin and Sequence of the Protozoan 



Fauna of Hay Infusions. Jour. Exp. Zool., 12, 1912. 



SARCODINA. 



AMOEBA PROTEUS. 



Amoebae are usually just discernible under the low power of 

 the microscope as irregular, semi-transparent, granular bodies. 

 Find a specimen in the material provided, which is known to con- 

 tain amcebse, and determine the following points: 



1. With the high power observe the peculiar method of loco- 

 motion, the constant but slow change in the shape of the body 

 by means of projections, pseudopodia, or " false feet." 



Make sketches at intervals of one or two minutes to show the 

 changes in the form of the body. 



2. Observe the peripheral zone of hyaline protoplasm, the 

 ectoplasm, and compare this with the inner protoplasm, the endo- 

 plasm. Observe in detail the formation of a pseudopodium. 

 Does the endoplasm extend into the pseudopodium? Can you 

 explain how the movement is caused ? 



3. Find a clear space which appears and disappears at inter- 

 vals; this is the contractile vacuole. Determine the length of 

 time between successive contractions. Are the intervals regu- 

 lar? When the vacuole contracts what becomes of the con- 

 tents? What is its function? 



4. Note the oval or rounded nucleus moving with the flowing 

 endoplasm. What is its structure? 



5. Food materials in process of digestion are readily seen. 

 Of what do they consist? They are contained in gastric vacu- 

 oks. By careful watching, it is often possible to observe the man- 

 ner in which food is ingested and the manner in which the undi- 

 gested matter is egested. 



