816 PROTOZOOLOGY 



macronucleus anterior; a micronucleus ; a contractile vacuole; fresh 

 or salt water. Several species (Busch, 1921). 



S. gyrans (Stokes) (Fig. 347, /). Lateral border with rounded ele- 

 vation near anterior end, posterior end truncate; 40-70/x long; in 

 standing fresh water. 



Family 3 Tintinnidae Claparede and Lachmann 



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

 composed of gelatinous or pseudochitinous substances; with longi- 

 tudinal rows of cilia, and 2 (1-4) macro- and a micro-nuclei; mostly 

 pelagic, a few inhabiting fresh or brackish water. Kofoid and Camp- 

 bell (1929) distinguished more than 300 species and placed them in 

 12 families and 51 genera, of which 23 genera were created by them. 

 A few genera and species are mentioned here. Taxonomy (Hofker, 

 1932); species (Campbell, 1942; Balech, 1942-1951; Rampi, 1950; 

 Silva, 1950); factors in evolution (Kofoid, 1930); lorica formation 

 (Busch, 1925). 



Genus Tintinnidium Stein. 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 water. 



T.fluviatile Stein (Fig. 347, g). Lorica 100-200juby 45ju; on vege- 

 tation in fresh water. 



T. semiciliatum Sterki (Fig. 347, h, i). 40-60/z long; on plants in 

 fresh water. 



Genus Strombidinopsis Kent. Lorica often absent; ovate or pyri- 

 form; frontal border with numerous long cirrus-like cilia; body 

 covered by fine cilia; contractile vacuole posterior; fresh water. 



S. gyrans K. (Fig. 347, j). 30-80/1 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. Species (Balech, 1945). 



T. cylindrata Kofoid and Campbell (Fig. 347, k). Lorica 40-50/c 

 long; in lakes. 



T. illinoisensis Hempel (Fig. 347, 1). Lorica 59/x long; in rivers. 



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

 divided externally and internally into a collar and bowl; collar with- 

 out spiral structure; in fresh water. 



C. crater a (Leidy) (Fig. 347, m). Lorica 60-70/i by 40/x; a number 

 of varieties are often mentioned. 



Family 4 Ophryoscolecidae Stein 



Elongate oval, asymmetrical; with 1 or 2 (adoral and dorsal) 

 zones of membranellae; in digestive tract of mammals. Sharp (1914) 



