MASTIGOPHORA, CHRYSOMONADINA 173 



of the latter group, includes important disease-causing parasites 

 of man and of domestic animals. 



The Mastigophora are divided into two subclasses as follows: 



With chromatophores Subclass 1 Phytomastigina 



Without chromatophores Subclass 2 Zoomastigina (p. 235) 



Subclass 1 Phytomastigina Doflein 



The Phytomastigina possess the chromatophores and their 

 usual method of nutrition is holophytic, though some are holozoic, 

 saprozoic 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 Phytomastigina. 



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. 184) 



Chromatophores green 



Simple contractile vacuole, anabolic products starch and oil. . 



Order 3 Phytomonadina (p. 188) 



Contractile vacuole complex 



Anabolic products paramylon. . Order 4 Euglenoidina (p. 203) 



Anabolic products oil Order 5 Chloromonadina (p. 213) 



2 flagella, one of which transverse. . . .Order 6 Dinoflagellata (p. 216) 



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 (rarely green or bluish) and usually discoid, 

 though sometimes reticulated, in form. Metabolic products are 

 refractile bodies, known collectively as leucosin (probably carbo- 

 hydrates) and fats. Starches have not been found in them. 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 obtain- 

 ing food materials which vary among different species. Nutrition, 

 though chiefly holophytic, is sometimes holozoic or saprozoic. 

 Contractile vacuoles are invariably found in freshwater forms, 

 and are ordinarily of simple structure, although a complicated 

 system seems to be found in some. 



