VORTICELLA. 



B XI 



Fig. 10. A group of Vorticellse : x 200. (c. h. h.) 



Pigs. I, II, and III show the animal in various positions. IV is a much smaller 

 specimen drawn to the same scale. V shows a specimen made to contract by 

 action of alcohol. VI is detached from its stalk, and swimming away freely disc 

 forward. VII, VIII, IX show three stages of fission. X, XI, and XII show the 

 separated individual swimming by means of the aboral circle of cilia : XI is slightly 

 contracted, XII strongly contracted after the cover-glass has been tapped. 



A, Food-vacuole discharging contents at anus. C, cilia of the disc. CF, con- 

 tractile fibre of stalk, d, disc. D', disc retracted. FV, food-vacuole. PH> 

 pharynx, pv, pulsating vacuole. P, peristome. M, myophan striation. N> 

 nucleus. V, vestibule. 



