CLASS INFUSORIA. 



FIG. T. 



PIG. 8. 



ORDER FLAGELLATA (fla jel' la ta). 



Flagellate (fia'jei lat) Infusorians are peculiar in that 

 they seldom possess more than one or two flagella, or 

 lashes. They are extremely minute and resemble in va- 

 rious respects the lower plants. They are, indeed, con- 

 sidered by many zoologists as the property of botanists. 

 They are distinct, however, in that their motions seem 

 to be more definite than those of -flagellate plants, in 

 possessing a contractile vacuole and 

 in using the flagellum to force bits 

 of solid food into a small opening at 

 its base, which answers for a mouth. 



The Green Euglena (ugle'na) often 

 appears on the surface of stagnant 

 pools, forming a green scum. Under 

 the microscope it is seen to move 

 rapidly about by lashing with its 

 flagellum. 



Oodosiga (ko dos' I ga) is a minute 

 form found in colonies* attached to 

 the stems of fresh-water plants. It 

 is peculiar in having the flagellum 

 surrounded by a collar. 



The Noctiluca (nok tl lu'ka) is of 

 interest, in that it has the power of 

 producing a phosphorescent light. 

 During cjuiet evenings of the sum- 

 mer months, millions of these animals rise to the surface 

 of the ocean, lighting the waves for miles in extent, with 



FIG. 7Eu glS'na mr'i dis. 

 Green Euglena. F, Flagellum 

 at base of which is an opening 

 through which food (/) may 

 be forced into the body sub- 

 stance. Pv, Pulsating vacu- 

 ole. N, Nucleus. (Greatly 

 enlarged.) 



FIG. 8. Co dfo'i ga bo trfj' ff. 

 Clustered Codosiga. S, Sup- 

 porting stem. Pr, Pulsating 

 vesicle or contractile vacuole. 

 N, Nucleus. <7, "Collar." 

 F. Flagellum. (Greatly en- 

 larged.) 



* Many of the flagellate forms are found collected in colonies. Each colony 

 presents either a tree-like or a spherical structure, new forms taking their places 

 in the old group. 



