76 DAVENPORT ACADEMY OF SCIENCES. 



Found often in great numbers associated with Chikviwnas 

 paramcechiin in pond water infusions. Reproduction by trans- 

 verse division. 



Glaucoma sp. (?) 



Body with dorsal surface convex and deeply grooved in a 

 longitudinal direction, flattened ventrall5\ Oral aperture indis- 

 tinct. Ventral surface clothed with cilia. Nucleus spherical, 

 central or near the dorsal border. Contractile vesicle posterior to 

 the middle of the body. Endoplasni usually filled with green 

 chroniatophores. 



lycngth, 50 microns. (Fig. 121, PI. XVI.) 



During the summer of 1905 a species as described above was 

 found abundantly in Lake Okoboji as well as other localities of 

 the state. 



The position and character of the oral aperture could not 

 definitely be determined, although what appeared to be an oral 

 membrane was sometimes visible on the ventral surface near the 

 anterior extremity. 



Green chroniatophores usually filled the organism, being 

 arranged in longitudinal rows between the grooves, but trans- 

 parent individuals free from chlorophyl have not infrequently been 

 observed. Nucleus seldom visible without the aid of reagents. 



Reproduction by transverse fission. 



Found in fresh water with aquatic plants. 



This species is conditionally placed in this genus. 



FRONTONIA Ehrenberg. 



Elongate-oval or elliptical. Oral aperture lateral, appearing as 

 a slit-like opening. Pharynx short with minute teeth. Surface 

 striated longitudinally. Trichocysts usually abundant. 



Frontonia leucas Ehr. 



Body elongate-oval, wider anteriorly. Oral aperture anterior 

 to the middle of the body. Cilia fine, arranged in longitudinal 

 rows. Contractile vesicles usually two in number. Trichocysts 

 very numerous. 



Eengtli, 250-300 microns. (Fig. 122, PI. XVI.) 



Frontonia Icucas is a common form in stagnant pond water, often 



