B. MOTILE STAGE. 



(i). After dried, resting forms have been in water for twelve 

 hours examine for motile forms and note their movements, 

 (a). An active transition from place to place. 

 (b). A rotary motion around the long axis. 

 (2). Note the following kinds of motile forms: 



(a). Large individuals, the macro-zoospores, of the same 

 size as the resting forms, each surrounded by a 

 thin colorless cell wall, separated from the contents 

 by a clear space. 



(b). Much smaller motile forms, each surrounded by no 

 separate cell wall, but with two cilia or flagella at 

 the pointed end or "beak". These are the micro- 

 soospores. 



(3). In the larger forms note: Color, structure, contents, sac 

 (cell wall), cilia, protoplasmic bridles. "Which end goes ahead in 

 swimming? How are the contents held in place within the sac? 

 In an individual which has nearly ceased movements study the suc- 

 cessive positions assumed by the flagella, and their mode of bend- 

 ing to and fro. Treat with iodine : the protoplasm is killed and the 

 cilia are rendered conspicuous. 



Draw individuals in motile stages to sJww all of the above men- 

 tioned points. 



VII. VOLVOX GLOBATOR. 



(A Flagellate Protophyte). 



Place a drop of alcohol containing Yolvox on a hollow-ground 

 slide cover and examine with low power. Having found a colony 

 as perfect as possible, observe with high power and draw the fol- 

 lowing : 



1. Form; spherical when not disturbed. 



2. Size ; variable depending upon age of colony. 



3. Structure ; a hollow sphere surrounded by a single layer of 

 cells (zooids) each of which in life bears two flagella and contains 

 chlorophyll, a nucleus and a stigma or eye spot. The zooids are 

 connected together by a gelatinous substance, and each is connected 

 by strands of protoplasm to the zooids immediately surrounding it. 



4. Life Cycle ; observe the cells which migrate into the cavity of 

 the sphere from the outer wall. These are the sex cells, which are 

 of two kinds: a. Parthenogonidia, which without fertilization give 



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