CHAPTER V 



SUBPHYLUM 1 PLASMODROMA DOFLEIN 

 CLASS 1 MASTIGOPHORA DIESING 



THE CLASS Mastigophora includes those Protozoa which 

 possess one or more flagella. Aside from this common 

 characteristic, the members of this class make a very heterogene- 

 ous assemblage. Since it includes a large number of chlorophyll- 

 bearing organisms, it seems to stand in the way of a sharp 

 distinction between the Protozoa and the Protophyta. Many of 

 its members have been, and still are, classified with the Proto- 

 phyta by botanists. 



In the majority of the Mastigophora, each individual pos- 

 sesses one to four flagella during the entire life-cycle except in 

 the encysted or palmella stage. In some forms there occur six 

 or eight flagella, and in Hypermastigida an enormous number of 

 flagella are usually found. The palmella stage (Fig. 29) is con - 

 mon among the Phytomastigina and, unlike the encysted stage, 

 is capable not only of metabolic activity and growth but also 

 of reproduction. Thus these forms show undoubtedly a close 

 relationship to the algae. 



All four types of nutrition, carried on separately or in 

 combination, are to be found among the members of the 

 Mastigophora. In holophytic forms, the chlorophyll is contained 

 in the chromatophores, which are of various forms among 

 difi'erent species (Fig. 15) and vary in color, being green, blue- 

 green, yellow, brown, reddish-brown, red, etc. The difference 

 in color is mainly due to the pigments which envelop the 

 chlorophyll. Many forms adapt their mode of nutrition to 

 changed environmental conditions, for instance, from holophy- 

 tic to saprozoic in absence of sunlight. Holozoic, saprozoic and 

 holophytic nutrition seem to be combined in Ochromonas. The 

 chromatophore frequently contains a refractile granule or body, 

 the pyrenoid (Fig. 15), which becomes the center of the forma- 

 tion of the paramylum body. Besides the latter, reserve food 



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