DIVISION EUGLENOPHYTA 



CLASS EUGLENOPHYCEAE 



This is a protozoan-like division of the Protista which is sharply 

 defined by unique and highly specialized features. The derivation 

 of the euglenoids is obscure, if not entirely unknown, although there 

 is some evidence that they have evolved from marine ancestors. 

 Most of the members in this division are fresh-water, however. 

 Although a few are sedentary, most forms are motile by 1 or 2 

 stout flagella of complex structure which arise apically from a small 

 reservoir and emerge through a canal. In the colorless members, and 

 also (though less evident) in the chlorophyll-bearing forms, there 

 is a gullet and a complex vacuolar system. Many euglenoids are 

 highly metabolic, and some may even adopt an amoeboid type of 

 motility and apparently never develop flagella {Euglena spp.). In 

 1 family, the Euglenaceae, there are disc-like, ribbon-like, or star- 

 shaped chloroplasts ( chloroleucites ) which contain a peculiar type 

 of chlorophyll. Pyrenoids are present in some of the members of 

 this division, as is also a red pigment-spot. 



In the holophytic (autotrophic) forms, food reserve is a starch- 

 like polysaccharide, paramylon, which is deposited in variously 

 shaped bodies. Unlike starch, it does not stain blue when treated 

 with iodine. See Fritsch (1935), Dangeard (1902), and Gojdics 

 ( 1934 ) on morphology of the cell. 



Reproduction is by longitudinal division of the cell, although 

 there are a few reports of conjugation and of isogamete fusion. 



The colorless forms are included in the two families Peranemaceae 

 and Astaciaceae, whereas the alga-like genera constitute the Euglen- 

 aceae, the only family considered here. 



Some authors recognize the family Colaciaceae for the epizoic 

 genus Colacium, and place the family in a separate order, Colaciales. 

 Accordingly, the Euglenaceae comprises the Euglenales. Here the 

 simplified arrangement used by Fritsch (1935) is followed. 



ORDER EUGLENALES 



FAMILY EUGLENACEAE 



This family includes the pigmented, holophytic euglenoids which 

 contain a peculiar type of chlorophyll, the chemistiy of which is 

 not well known. In addition to this pigment there may be haemato- 

 chrome which appears when the organisms are subjected to intense 

 illumination or, in a few forms, may be present at all times. The 

 chlorophyll is localized in definitely and specifically shaped chloro- 



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