37° APPENDIX. 



C. OSCILLARIA. 



1. Observe the color of a bit of Oscillaria; contrast it with that 

 of Pleurococcus. (•[ n.) 



2. With needles tease out the specimen in a drop of water on a 

 glass slip; observe the delicate thread-like form. (Fig. 15.) 



3. Transfer a bit of living Oscillaria to a small glass dish or 

 white individual butter plate with a little water; protect it from 

 drying up with a cover; 24 hours later observe the position of 

 the filaments. (•[ 14.) 



4. Demonstration. Dip a considerable mass of Oscillaria in hot 

 water for a moment and put in a white butter plate with as small 

 a quantity of water as will cover it. As the water evaporates 

 observe the color deposited on the dish at the edge of the water. 



or no 



D. SPIROGYRA. 



If fresh material is available examine a few filaments in a white 

 dish for color. If preserved material is used, stain red by 

 immersing for a few minutes in eosin (cheap red ink will answer). 



Examine with a lens. Observe: 



1. Length; whether broken or whole; whether with or without 

 branches. 



2. The delicate partitions, like white lines, crossing the green 

 (or red) filaments, dividing the protoplasm of one cell from 

 another. Can the form of the chforoplasts be seen? (Cf. fig. 24.) 

 This can be readily seen only in the larger species. (T 25.) 



3. Demonstration. Mount a few fresh filaments in water. 

 Show under moderate power the form of the chloroplasts; the 

 reserve food nodules; the nucleus. (Fig. 24.) 



4. Examine conjugating specimens with a lens after staining. 

 Observe the conjugating tubes connecting two filaments like rungs 

 of a ladder (Tf 361); the zygotes or zygospores (^[365) as blackish 

 dots in some cells. Are they in one filament only or in both ? 



5. Demonstration. Mount conjugating filaments and show 

 the conjugating tubes and zygospores. (If 375, fig. 303.) 



E. CLADOPHORA. 



If fresh material is at hand observe in a white dish; if pre- 

 served specimens are used stain for a few minutes in eosin. 

 I. How is the plant attached? 



