EDMONDSON — PROTOZOA OF IOWA. 79 



Uronema MARINUM Duj. 



Body elongate-ovate, usuall}' more than twice as long as broad. 

 Cilia arranged in longitudinal rows. One long seta produced 

 from the posterior border. Oral aperture lateral with a membrane 

 more or less elongated but not greatly extended. Nucleus 

 central. Contractile vesicle posterior. 



L,ength, 30 microns. (Fig. 126, PI. XVI.) 



In general contour this species somewhat resembles Cydidium 

 glaucoma, but is larger and the cilia instead of being rigid are 

 exceedingly vibratile, their movement being irregular and inde- 

 pendent. The oral membrane of Uronema is not so highly 

 extensile as in Cydidium . 



Found in fresh water, often associated with Cydidium but not 

 nearly so abundant. 



COLPIDIUM Stein. 



Somewhat kidnej'-shaped, persistent in form. Oral aperture a 

 little distance from the anterior extremity. Pharynx with a 

 slightly protruding, undulating membrane. 



CoLPiDiuM striatum Stokes. 



Body about twice as long as broad, the anterior extremity 

 slightly curved toward the ventral aspect. Nucleus usually 

 central. Contractile vesicle posterior. 



Length, 60 microns. (Fig. 128, PI. XVII.) 



Colpidium striatum is a common and widely distributed form 

 found in pond water. In general appearance it resembles Col- 

 pidium cucullus Schrank, (not observed in this state) which, how- 

 ever, possesses two nuclei. 



Reproduction takes place by transverse division. 



COLPODA Miill. 



Resembling Colpidium in general outline, compressed laterally. 

 Oral aperture ventral, in a cleft-like depression. Cilia around the 

 mouth longer than those of the general surface. 



Stokes has described several species under the generic title 

 Tillina which probably should be retained within the genus 

 Colpoda. 



