364 UNIVERSITY or COLORADO STUDIES 



Elongate, nearly cylindrical, the anterior extremity truncate and slightly curved; 



length 40-70 M Loxocephalus granulosus S. K.* 



Elongated, bean-shaped both extremities evenly rounded, the anterior one curved 

 ventraUy; length 100-120 m (very abundant) .... Colpoda helia Stokes* 

 Dr. Edmondson also reports a second species of this genus . . C. campyla Stokes* 



20. Peristome not evident; mouth near the front; body oval, 75 fi long 



Glaucoma scintillans Ehr. 

 Persitome evident, posterior to middle; a tuft of long bristles at the posterior end; 



length 30 M Cinetochilum margaritaceum Ehr. 



Peristome evident, not, or not wholly, posterior to middle 21. 



21. Peristome covering the whole right side, with a large membrane; length 50-100 /it 



Lembadion bullinum Perty 

 Small (20 fi), ovate, with a posterior seta much longer than the cilia of the general 

 surface (very abundant) Cyclidium glaucoma Ehr. 



22. Elongated, wath a neckhke prolongation 23, 



Elongated-oval, without a neck; cilia arranged in longitudinal rows 



Chilodon cucullulus Miill. 



23. Larger (length 110 m), contractile vesicle single, posterior (very abundant) 



Lionotus fasciola Ehr. 

 Smaller (80-100 m), contractile vesicles numerous Lionotus pleurosigma Stokes* 



24. Mouth near or posterior to middle of body, preceded by a narrow peristomal 

 furrow; greatly elongated but highly contractile, contracting spirally (very 



abundant) Spirostomum teres C. & L.* 



Peristome occup}dng the front border; body entirely ciliate; body blue, when ex- 

 tended 250-300 M long; often in clusters Stentor casruleus Ehr. 



Body with anterior ring of cilia; shape spheroidal, length 25 /x 



Halteria grandinella Miill. 



25. Elongated-oval or elliptical, very elastic; three prominent frontal styles, and five 

 • anal styles; length 80-100 m Oxytricha pellionella Miill. 



Persistent in shape, inflexible, oval, ventral surface flattened, dorsal surface con- 

 vex and longitudinally furrowed; seven frontal styles and three ventral; length 



80 fi (very abundant) Euplotes charon Miill. 



Small (35 m); convex dorsal surface \\'ith five or six longitudinal furrows; usually 

 three frontal styles, four or five scattered ventral and five anal Aspidisca costata Duj. 



26. Stalk not retractile, slender, dichotomously branched, secondary divisions very 



long Epistylis plicatilis Ehr.* 



Stalk retractile 27. 



27. Body broadly campanulate, greatly dilated anteriorly; stalk usually five or six times 

 length of body; endoplasm dark granular, often opaque; length of body 150 m 



Vorticella campanula Ehr.* 



Body oval, wider centrally, anterior border not greatly dilated : stalk about three 

 times length of body; endoplasm transparent; length of body 55 m; occurring 



in social groups Vorticella alba From.* 



Body conical, elongate, tapering posteriorly; stalk not much longer than body; 

 length of body 40-50 m; solitary in its habits Vorticella telescopa S. K.* 



28. Body inhabiting a lorica which is produced posteriorly into a rigid stalk Acineta sp.* 

 Spherical, without a shell, attached by a slender but rigid stalk; diameter of body 

 .'>.') M (very abundant) Podophrya fiia Miill.* 



76 



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