256 PROTOZOOLOGY 



The Mastigophora are divided into two subclasses as follows : 



With chromatophores Subclass 1 Phytomastigina 



Without chromatophores Subclass 2 Zoomastigina (p. 333) 



Subclass 1 Phytomastigina Doflein 



The Phytomastigina possess the chromatophores and their usual 

 method of nutrition is holophytic, though some are holozoic, sapro- 

 zoic or mixotrophic; the majority are conspicuously colored; some 

 that lack chromatophores are included in this group, since their 

 structure and development resemble closely those of typical Phyto- 

 mastigina. 



Some observers consider the types of flagella as one of the char- 

 acters in taxonomic consideration (Petersen, 1929; Vlk, 1938: Owen, 

 1949; etc.). Owen found, for example, "lash flagella" (with a terminal 

 filament) in some species of Phytomonadina, Rhizomastigina, Pro- 

 tomonadina and Polymastigina and simple flagella in the forms in- 

 cluded in Chrysomonadina, Cryptomonadina, Euglenoidina and 

 Dinoflagellata; and simple flagellum and flagella on Oikomonas and 

 Monas. He advocated the transfer of the latter two genera from 

 Protomonadina to Chrysomonadina. 



1-4 flagella, either directed anteriorly or trailing 

 Chromatophores yellow, brown or orange 



Anabolic products fat, leucosin Order 1 Chrysomonadina 



Anabolic products starch or similar carbohydrates 



Order 2 Cryptomonadina (p. 272) 



Chromatophores green 



Anabolic products starch and oil. Order 3 Phytomonadina (p. 276) 



Anabolic products paramylon Order 4 Euglenoidina (p. 293) 



Anabolic products oil Order 5 Chloromonadina (p. 306) 



2 flagella, one of which transverse Order 6 Dinoflagellata (p. 310) 



Order 1 Chrysomonadina Stein 



The chrysomonads are minute organisms and are plastic, since 

 the majority lack a definite cell- wall. Chromatophores are yellow to 

 brown and usually discoid, though sometimes reticulated, in form. 

 Metabolic products are leucosin and fats. 1-2 flagella are inserted at 

 or near the anterior end of body where a stigma is present. 



Many chrysomonads are able to form pseudopodia for obtaining 

 food materials which vary among different species. Nutrition, though 

 chiefly holophytic, is also holozoic or saprozoic. Contractile vacuoles 

 are invariably found in freshwater forms, and are ordinarily of 

 simple structure. 



Under conditions not fully understood, the chrysomonads lose 



