EDMONDSON — PROTOZOA OF IOWA. 75 



spherical, centrally located. Contractile vesicle posterior to the 

 nucleus. Ivndoplasm usually transparent. 



Length of body, 40 microns. (Fig. 118, PI. XV.) 

 This species has been found abundantly in long-standing infu- 

 sions of pond water. It is a swift moving animalcule progressing 

 in a straight course, usually rolling on its longitudinal axis. 

 Reproduction takes place by transverse division. 



LEUCOPHRYS Ehreuberg. 



Ovate, broadly rounded posteriorly, somewhat truncate anter- 

 iorly. Peristome short and broad, harp-shaped and confined to 

 the anterior region. Pharynx distinct. Cilia of the left-hand 

 border of the peristome larger than those of the general surface. 



Leucophrys patula Ehr. 



Body oval, persistent in shape, the anterior extremity obliquely 

 truncate. Peristome broadly harp -shaped. Pharynx tubular, 

 curved. Surface longitudinally striate. Nucleus band-like, 

 curved, centrally placed. Contractile vesicle posterior. 



Eength, 200 microns. (P"ig. 119, PI. XV.) 



Rarely found in this state. Habitat, fresh water among algae. 



GEAUCOMA Ehrenberg. 



Somewhat oval, ventral surface flattened and ciliated, dorsal 

 surface convex, sometimes furrowed. Oral aperture on the ven- 

 tral surface, provided with a vibratile membrane. Nucleus spher- 

 ical. Contractile vesicle single. 



Galucoma scintii^lans Ehr. 



Body oval, ventral surface ciliated. Oral aperture a little dis- 

 tance from the anterior extremity with the vibrating membrane 

 extending around it, presenting a bilabial appearance. Nucleus 

 large, spherical, situated in the central region. Contractile vesicle 

 single, in the posterior region. 



Length, 75 microns. (Fig. 120, PL XVI.) 



When viewed laterally the oral membrane protrudes as a single 

 tongue-like process, but from a ventral view-point the bilabial 

 character is evident, the lips usually vibrating slowly, opening 

 and closing the oral aperture. 



