EUGLENA, VOLVOX 33 



mis enables it to live in clear water, being nourished like 

 other green plants. (Minchin, p. 14.) 



4. Note the absence of color near the anterior and pos- 

 terior ends of the organism. Near the anterior end also 

 notice the red pigment spot, or stigma. What is its probable 

 function? 



5. Stain a specimen with iodine and look for the nucleus. 

 It is somewhat obscured by the chlorophyl. 



6. Observe specimens in the resting stage. 



Make a drawing showing all of the points observed. 

 Look through the stock cultures for other forms of plant 

 flagellates, such as Trachelomonas, Phacus, etc. 



It is desirable to make drawings of the different forms. 



Klebs: Ueber die Organisation einiger Flagellatengruppen und ihre 

 Beziehungen zu Algen und Infusorien. Unt. Bot. Inst. Tubingen, 1, 

 1883. 



: Flagellatenstudien. Zeit. f. wiss. Zool., 55, 1893. 



Walton: Review of the Order Euglenoidina. Ohio State Univ., 1915. 



Baker: Studies in the Life History of Euglena. Biol. Bull., 51, 1926. 



VOLVOX 



Volvox globator is better for study than V. aureus. It 

 may be distinguished from the latter by the larger size of 

 the colony, the greater number of cells that compose it 

 (about 15,000), the angular shape of the individual cells, and 

 the stout connecting processes of protoplasm, into which 

 chromatophores may enter. 



Observe the movements of colonies in a watch glass of 

 water, with the naked eye and with a low power of the 

 microscope. 



1. Do the colonies tend to collect toward a particular side 

 of the dish? What reason is there for the reaction? Does 

 an individual Volvox colony move with reference to one axis? 



2. Place a number of colonies on a slide with enough 

 water to allow them to be covered without crushing them. 

 Study first with the low and then with the high power and 



3 



