ing no trichocysts, and less distinct than in Paramecium: two nuc- 

 lei about one third of the animal's length from either end : one con- 

 tractile vacuole : a buccal groove, much like that of Paramecium ; 

 along the left side of the groove a row of long powerful cilia. Three 

 groups of gigantic cilia on the ventral surface. The cilia of the 

 anterior and middle groups are hook-like, those of the posterior 

 group paddle-shaped. Along the margin of the ventral side is a 

 row of large cilia, three of which project posteriorly as long bristle- 

 like processes. Observe the method in which all three sorts of cilia 

 are used. 



Make a drawing to show all the structural features of Stylonychia. 



IV. AMOEBA PROTEUS. 



(A Rhizopod Protozoon) 



Place a small drop of sediment from a vessel containing Amoeba 

 on a slide with a drop of water ; cover with cover glass and search 

 for Amoeba with low power. If not easily found, prepare several 

 such slides and examine them after they have been standing for 

 some minutes, so that the Amoebae may crawl out of the sediment. 

 When an Amoeba is found examine with a high power and note : 



A. MORPHOLOGY. 



1. Size; is it visible to the naked eve? 



J 



2. Shape; is it regular? Constant? Are the pseudopodia of 

 the same size and shape ? Do they ever branch ? How many do 

 you find ? Sketch at intervals of one minute for five minutes. 



3. Structure : An outer clear layer, the ectosarc, and an 

 inner granular more opaque substance, the endosarc (endoplasm). Is 

 the boundary between the two layers a sharp one ? \Yhere is the 

 ectosarc thinnest? Is there a membrane outside this layer? Are all 

 the granules of the endosarc of the same size? Which layer is 

 the more fluid ? In the ectosarc a clear vesicle may be found which 

 appears and disappears; this is the contractile vacuole. How long 

 does it take it to contract, how long to expand ? Are there any 

 visible contents ? Is there more than one contractile vacuole ? 



In the endosarc a round, clear body may be found, which does 

 not change shape ; this is the nucleus. Is it more solid than the 

 surrounding protoplasm? What is its shape? Size? Is it always 

 in the same place? There are often also in the endosarc various 

 foreign bodies which serve as food, such as diatoms, desmids, green 

 cells, etc. Draw to show structure. 



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