58. Sheath with a short stem 



Cothurma Ehrenberg 

 No definite stem 59. 



59. Upright, attached at base 



Vagmicola Lamarck 

 Recumbent, attached along side 

 Platycola Kent 



60. Stem spirally coiled, unbranched 



Vorticella Linn. 

 Stem branched, with several animals in groups at the ends 61. 



6L Animals, but not the main stem, contractile 



Epistyhs Ehrenberg 

 Both stem and animals contractile 62. 



62. Branches of the stem contracting independently of each other 



Carchesium Ehrenberg 

 Branches all contracting together 

 Zoothammum Bory 



63. With one or two rings of long cilia 64. 

 Cilia not arranged in rings, except sometimes to encircle the mouth 



region 67. 



64. Animal drum- or barrel-shaped, with a posterior ring of cilia; usually 



living on Hydra, amphibians, etc. 

 Trichodma Ehrenberg 

 Animal cocoon- or thimble-shaped, with one or two rings of cilia around 

 the body; usually free-swimming 65. 



65. With a tail-like process 



Urocentrum Nitzsch 

 No tail-like process 66. 



66. Body spherical, with a belt of very long cilia around the middle; moving 



by jerks 



Halteria Dujardin 

 Body thimble-shaped, with the flat end bearing a knob-like projection on 

 which is the mouth; with two belts of cilia 

 Didinium Stein 



67. With a shell of small, regularly arranged plates 



Coleps Nitzsch 

 No shell 68. 



68. With one to five long bristles or spines on rear of animal 69. 

 Not so 7L 



69. With cilia all over the body; usually with one to several posterior bristles 



Cvclidnirn Miiller 

 No cilia on the dorsal surface; usually with three to five terminal 



bristles 70. 



70. Body elongated; usually with three posterior bristles 



Stylonychia Ehrenberg 

 Body oval; about five posterior bristles 

 Euplotes Ehrenberg 

 7L Body trumpet- or bag-shaped, with a row of cilia around the funnel- 

 shaped mouth area 72. 

 Not so 73. 



44 



