VORTIGELLA. 



B XI 





Fig. 10. — A group of Vorticellse ; 



x220. 



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

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

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

 disc forward. YII. YIII, 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, contractile fibre of stalk. JD, disc. D', disc retracted. FV, food-vacuole. 



PEC, pharynx. PV", pulsating vacuole. P, peristome. JVE, myopliau striation. 

 N, nucleus. V, vestibule. 



