iS8 



ZOOLOGY 



Pig. 70. 



Fig. 71. 



•n IT ,^l> 



Fig. 70. A, VorticeUa, a stalked cHiate Infusorian; i, contracted; 2, extended. /, food 

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

 disc; t'V., pulsating vacuole; s, stalk. B, a colonial type similar to VorticeUa, 



Questions on the figtires. — Compare the internal structure of VorticeUa with 

 that of Paramecium (Fig. 68). What are the principal diflferences? 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 green flagellate, i, typical swimming 'condition; 2, somewhat 

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

 cyst; /, fiagellum; 71, nucleus; o, mouth; J.ii., pulsating vacuole; sp, pigmei^t spot. 



B, Podophrya, & stalked Infusorian bearing tentacles (l), pt Infusorian captured for food; i, 

 ■talk. 



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 

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

 in the latter? 



