infus6ria. 



157 



a. Body large, trumpet-shaped, greenish; often 

 without a visible sheath, and when one is 

 formed it is sometimes soon abandoned, the 

 Stentor swimming about freely. The body is 

 slightly changeable in shape. Several Stentors 

 of this species are often found close together, 

 having formed in common a soft sheath divided 

 into irregular compartments, one. for each In- 

 fusorium. S. polymdrphus. Fig. 114. 



a^ Body long, and narrowly trumpet-shaped, the 

 frontal region divided into two lobes, one of 

 which is almost at right angles to 

 the other. 'I'he body has many ^4^^,^^ 

 long, fine, stiff hairs (setse) pro- 

 jecting from it, and visible under 

 a high-power (.^--inch) objective. 

 The sheath is always present. It 

 is narrow, cylindrical, brown, and 

 about one-half as long as the ex- 

 tended body. This Stentor is 

 never free-swimming, and is never 

 found 'in company with others of 

 the same species. It is not un- 

 common on Ceratophyllum and on 

 other aquatic plants. 6'. Bar- 

 rMi, Fig. 115. 

 b. Body green or red, the red color 

 often limited to the part just be- 

 neath the wide frontal border 

 where the circle of large cilia is. Sometimes 

 the red color is diffused over the whole body, 

 but usually the green matter so obscures it that 

 it remains invisible unless specially looked for_ 



Fig. I 5. — Stentor 

 - Barritti. 



