GENERAL BIOLOGY 



(3). Look for individuals in the process of division, some elon- 

 gated with transverse lines of division, others divided into two or 

 more smaller portions often lying within the sac of the parent. 

 Draw various stages in this reproduction by fission. 



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 proto- 

 plasmic body by a clear space, which is bridged by 

 protoplasmic strands ("bridles"). 



(b). Much smaller motile forms, each surrounded by 

 no separate cell wall, but with two flagella at the 

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

 zoo spores. 



(3). In the macro-zoospores, note: Color, structure, contents, 

 sac (cell wall), flagella, 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 concessive positions assumed by the flagella and their 

 mode of bending to and fro. Treat with iodine: The protoplasm 

 is killed and the flagella are rendered conspicuous. 



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

 tioned points. 



EUGLENA VIRIDIS. 

 (Flagellata, Plant or Animal?) 



Read: Parker, Elementary Biology, pp. 44-4; or 



Parker and Parker, Practical Zoology, pp. 251-258. 



Place a drop of water containing Euglena on a slide, and after 

 covering look with the low power for green spindle-shaped organ- 

 isms which swim swiftly. Having found them study with the high 

 power and note: (i) Size. (2) Color due to chlorophyll. The 

 anterior end is colorless. Near the anterior end is a red pigment 

 spot, the stigma. (3) Shape, fusiform; the anterior end is blunter 



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