IX 



ANIMAL BEHAVIOUR 



161 



error behaviour. There is a trumpet-shaped ciliated 

 Infusorial! called Stentor which abounds in marshy pools, 

 attaching itself by the narrow end to water-weed, and 



FIG. 48. STENTOR. 



In this Infusorian there are cilia over the whole surface and specially 

 large cilia in a spiral wreath (C) around the mouth. 



The lower part is surrounded by a mucus-like sheath or tube (T). 



The macro-nucleus (A T ) is peculiar in being an elongated wavy band. 

 There are numerous micro nuclei. Bubbles of water, " food-vacuoles " 

 (V), surround the particles of food that have been taken in. A pulsating 

 area or contractile vacuole (CV), with excretory significance, is also shown 

 not far from the mouth. 



There are longi tudinal striations indicative of special threads (my onemes) 

 of contractile protoplasm. Stentor is often bright green, which is due to 

 the presence of numerous minute Algae (Zoochlorellse) living in symbiosis 

 with it. 



12 



