VORTICELLA. 



Mount in water a fragment of a submerged leaf or 

 other substance to which vorticelloe are attached. 

 Examine first with AA 2. Observe form and 

 movements. Look for a quiet specimen and study 

 with D 2. When it is extended, observe : 



General Characters. 



1. Form : bell-shaped. The bell attached by 



its smaller end to a stalk. 



2. Parts: 



(a) The conspicuous rim, the peristome, sur- 



rounding : 



(b) The disk : which closes the mouth of the 



bell. 



(c) Part of the disk raised above the peri- 



stome at one side, the epistome. 



(d) Cilia : bordering the peristome and the 



epistome. 



(e) A space between the peristome and the 



epistome, the vestibule. 



(/) The mouth : opening from the vestibule 

 into : 



(g) The oesophagus. 



(h) A definite region of the vestibule, the 

 anal spot, through which waste matter is 

 passed out from the body (visible only at 

 the time of passing out of waste matter). 



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