PROTOZOA 



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FIG. 70. 



FIG. 71. 



FIG. 70. A, Vorticella, a stalked ciliate Infusorian: i, contracted; 2, extended. /, food 

 "vacuoles"; g, gullet; m, contractile fibre (muscular); w, nucleus; o, mouth, surrounded by ciliated 

 disc; p.v., pulsating vacuole; s, stalk. B, a colonial type similar to Vorticella. 



Questions on the figures. Compare the internal structure of Vorticella with 

 that of Paramecium (Fig. 68). What are the principal differences? Likenesses? 

 How is a colonial type (as B} formed? How are new colonies started? In what 

 way does the animal become extended after contraction? Compare living 

 animal. 



FIG. 71. A, Euglena viridis, a flagellate Infusorian. i, typical swimming condition; 2, some- 

 what contracted; 3, spherical resting condition; 4, encysted stage in which fission has taken place. 

 c, cyst;/, flagellum; n, nucleus; o, mouth; p.v., pulsating vacuole; sp, pigment spot. 



B, Podophrya, a stalked Infusorian bearing tentacles (<) P> Infusorian captured for food; s, 

 stalk. 



Questions on the figures. How does multiplication in Euglena differ from that 

 of Paramecium? What are the differences in the method of feeding employed in 

 Vorticella and in Podophrya? What is the structure and function of the tentacles 

 in the latter? 



