506 BIOLOGY OF THE PROTOZOA 



Family 1. Frontoniidae Kahl 1926. 



1 1. Three ciliated structures on inside, left an 



outer membrane; below it an inner mem- 

 brane and right, at bottom, a 3-row cilia 



combination 12 



Only one strong membrane from left edge 



beats into ectoplasmic lip Genus Pseudoglaucoma Kahl 



12. Mouth near middle of ventral surface; dor- 



sal ciliated rows bent to right. . . .Genus Glaucoma Ehr. 

 Mouth on right edge of ventral surface; 



dorsal rows bend sharply to right . Genus < 'olpidium Stein 



13. Mouth with 2 or 3 membranes 14 



Mouth with only 1 membrane 16 



14. Slime dwelling; membranes surround 



mouth at pole, forming pocket behind 



Genus Cyrtolophosis Stokes 

 Naked forms; mouth without pocket 15 



1 5. One free membrane on both sides of mouth ; 



anterior rounded Genus Dichilum Schewiakoff 



One free membrane on right side, 2 others 

 in oral pit; anterior sharply pointed 



( !enus Paraglaucorna Kahl 

 1(3. Left and anterior membrane cover mouth 



cap-like Genus Stegochihim Schewiakoff 



Membrane not cap-like 17 



17. Membrane inserted inside and continues 



into posterior funnel IS 



Mouth without funnel continuation 19 



18. Form elongate-oval; slightly compressed 



Genus Monochilum Schewiakoff 

 Small, flattened, kidney-shape Genus Chasmatostoma Engelmann 



19. Mouth at or near anterior pole 20 



Mouth distinctly separate from pole 21 



20. Mouth a deep pit in the truncated end ; in 



jelly of egg masses Genus Espejoia Burger 



Mouth a narrow slit quite near anterior 

 pole Genus Malacophrys Kahl 



2 1 . Spindle form ; delicate groove from pole to 



small mouth Genus Bizone Lepsi 



Mouth without groove; membrane on left 

 side ( ienus Aristerostoma Kahl 



22. Cilia arranged in 1 or in 3 girdles 23 



Cilia in longitudinal rows; not arranged in 



girdle 24 



23. Very small (20,u) ; only 1 median girdle; 



1 caudal filament Genus Urozona Schewiakoff 



Caudal cilia many, fused; 2 broad girdles, 

 1 anterior, 1 posterior to oral girdle 

 (Fig. 205) Genus Urocentrum Nitzsch 



24. Mouth in center or anterior to center of 



body 25 



Mouth posterior to center of body 33 



25. Body compressed laterally; small furrow 



from anterior pole with membrane on 



right side and thick cilia on left . . .Genus Rhinodisculus Mansfeld 

 Bodv not laterally flattened 26 



