DIVISION CHLOROMONADOPHYTA 



CLASS CHLOROMONADINEAE 



This is a little-understood group of the Protista which is repre- 

 sented by only a few known forms. Some of the characteristics they 

 possess indicate an affinity with the Euglenophyta, while others are 

 suggestive of the Pyrrhophyta. In general, the Chloromonadophyta 

 are distinctly protozoa-like, and there are no filamentous or coccoid 

 expressions known in the division. 



The organisms are motile, ovoid, or pyriform unicells, often 

 dorsiventrally flattened, with a ventral furrow. There are 2 apically 

 attached flagella, 1 of which is usually trailing, as in some of the 

 Euglenophyta and Pyrrhophyta. In the pigmented members (2 gen- 

 era are colorless), there are numerous ovate and disc-like chloroplasts 

 in which xanthophyll is a predominant pigment. Neither starch nor 

 paramylon occurs as a food reserve, but instead, fats and oils. 



A characteristic common to several forms is the presence of 

 radially disposed trichocysts in the peripheral region of the cell. 

 These throw off threads upon stimulation. 



As far as is known, reproduction occurs by longitudinal cell di- 

 vision (as in the somewhat common Vacuolaria virescens Cienk. ). 



FAMILY CHLOROMONADINACEAE 



Characteristics as described for the class. Only one genus is 

 represented in our collections. 



GONYOSTOMUM Diesing 1866, pp. 298, 332 



Cells motile, dorsiventrally flattened, obovate or obovate-lanceolate 

 in front view and often showing a short caudus; dorsal surface 

 convex, the ventral surface flattened and with a longitudinal furrow 

 extending posteriorly from an opening which leads into a colorless 

 3-cornered cavity in the anterior region; flagella 2, usually longer 

 than the body, 1 projected forward, the other trailing; chloroplasts 

 numerous ovoid discs, crowded at the periphery; short radiating, 

 rod-like trichocysts also at the periphery, extending toward the 

 center of the cell ( often only a few of these show in the unstained, 

 living cell); pigment-spot wanting; food reserve in the form of oil. 



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