localized in (usually) 2 parietal and (in our specimens) laminate 

 chromatophores which may possess pyrenoids. Both starch ( staining 

 blue with iodine) and oil are produced as food reserves. The cells 

 are uninucleate and possess a contractile vacuole. In some forms 

 trichocysts border the furrow. There are 3 subgroups, one of which 

 is without pigmentation. 



Key to the Genera 

 Gullet absent Chroomonas 



( Cryptoclirysideae ) 

 Gullet present Cnjptomonas 



( Cryptomonadeae ) 



CHROOMONAS Hansgirg 1885, p. 230 

 Cells swimming by 2 apical flagella, dorsiventrally flattened, 

 elongate-ellipsoid or pyriform, broader toward the anterior end, 

 which is unsymmetrically bilobed, narrowed but broadly rounded 

 at the posterior end; longitudinal furrow narrow and shallow, with- 

 out a gullet, extending farther on the ventral surface than on the 

 dorsal; chromatophores 2 lateral parietal bands. 



Chroomonas Nordstedtii Hansgirg 1885, p. 230 



PI. 95, Fig. 45 



Cells slipper-shaped, broader toward the anterior end, which is 



unsymmetrically bilobed; narrowed posteriorly but broadly rounded 



at the pole; chromatophores 2 broad, parietal bands; cells 9-1 6;a 



long, 4-8/x in diameter. 



Common in shallow water of lakes and among algae masses and 

 decaying vegetation; in shallow pools and bogs. Wis. 



CRYPTOMONAS Ehrenberg 1838, p. 40 

 Cells slipper-shaped, dorsiventrally flattened, convex on the 

 dorsal surface, flat or concave ventrally, with a broad and con- 

 spicuous longitudinal furrow from which a gullet extends inwardly 

 from the anterior end; flagella 2, attached on the ventral surface at 

 the anterior end; chromatophores 1 or 2, lateral and parietal; starch 

 grains often present in the form of short rods; trichocysts sometimes 

 discernible along the margins of the furrow; contractile vacuoles 1-3. 



Key to the Species 



Gullet extending scarcely to the middle of 



the cell; cells 15-32,u long C. erosa 



Gullet longer, extending nearly % the length of 



the cell; cells larger, up to 80^ long C. ovata 



[441] 



