SPIROTRICHA, OLIGOTRICHA 589 



Family 2 Strobilidiidae Kahl 



Genus Strobilidium Schewiakoff. Pyriform or turnip-shaped; 

 cytostome at anterior end; without cytopharynx; horseshoe- 

 shaped macronucleus anterior; a micronucleus; a contractile 

 vacuole; fresh or salt water. Several species. 



S. gyrans (Stokes) (Fig. 266, /). Lateral border with rounded 

 elevation near anterior end, posterior end truncate; 40-70^i long; 

 in standing fresh water. 



Family 3 Tintinnidiidae Claparede et Lachmann 



Conical or trumpet-like, attached inside a lorica of various 

 forms, composed of gelatinous or pseudochitinous substances; 

 with longitudinal rows of cilia, and 2 (1-4) macro- and micro- 

 nuclei; mostly pelagic, a few inhabiting fresh or brackish water. 

 Kofoid and Campbell (1929) distinguished more than 300 species 

 and placed them in 12 famihes and 51 genera, of which 23 genera 

 were created by them. A few genera and species are mentioned 

 here. 



Genus Tintinnidium Kent. Elongated lorica, highly irregular 

 in form; soft; aboral end closed or with a minute opening; wall 

 viscous and freely agglomerates foreign bodies; salt or fresh wa- 

 ter. 



T. fl.uviatile (Stein) (Fig. 266, g). Lorica 100-200m by 45^; on 

 vegetation in fresh water. 



T. semiciliatum (Sterki) (Fig. 266, h, i). 40-60^ long; on plants 

 in fresh water. 



Genus Strombidinopsis Kent. Lorica often absent; ovate or 

 pyriform; frontal border with numerous long cirrus-like cilia; 

 body covered by fine ciUa; contractile vacuole posterior; fresh 

 water. 



S. gyrans K. (Fig. 266, j). 30-80/i long; fresh water pond. 



Genus Tintinnopsis Stein. Lorica bowl-shaped; always with a 

 broad aperture; aboral end closed; wall thin and covered with 

 foreign bodies ; salt or fresh water. 



T. cylindrata Kofoid et Campbell (Fig. 266, k). Lorica 40-50;i 

 long; lake water. 



T. illinoisensis Hempel (Fig. 266, I). Lorica 59^ long, in river. 



Genus Codonella Haeckel. Lorica urn- to pot-shaped; sharply 

 divided externally and internally into a collar and bowl; collar 

 without spiral structure; in fresh water. 



