PAPENFUSS: CLASSIFICATION OF THE ALGAE 149 



Order SIPHONOTESTALES Lemmermann (1901a, p. 92) 



Family Dictyochaceae Lemmermann (1901a, p. 92) 



According to Gemeinhardt (1930, pp. 22, 77), Scluilz established a fam- 

 ily Cornuaceae for the monotypic genus Cormia Schulz (1928, p. 285), 

 but I can find no mention of such a family in Schulz's writings. 

 Order STEREOTESTALES Lemmermann (1901a, p. 93) 

 Family Ebriaceae Lemmermann (1901a, p. 93) 



APOCHROMATIC GROUPS OF UNCERTAIN SYSTEMATIC POSITION 



Klebs (1892, pp. 282-283) and Semi (1900, p. 152) even in their time al- 

 ready suspected a relationship between certain colorless flagellates belonging 

 to the family ]\Ionadaceae and certain pigmented chrysomonads of the family 

 Ochromonadaceae. Subsequent work by a number of investigators (Scherffel, 

 1911, 1924; Pascher, 1916a, 1917, 1930b; Korshikoff, 1929, among others) have 

 amply substantiated the suspicions of Klebs. It is generally agreed today that 

 many of the colorless species are derived from pigmented species or are perhaps 

 only colorless forms of pigmented species. These forms not only agree with their 

 pigmented counterparts in the general morphology of the cell, type of flagel- 

 lation, and kind of food reserve but they also produce cysts of the same kind. 

 Consequently the families Oicomonadaceae and IMonadaceae have in the pre- 

 ceding treatment of the Chrysophyceae been accorded positions in the Chryso- 

 monadales and Ochromonadales, respectively. 



Klebs (1892) recognized two groups of colorless flagellates, the Protomas- 

 tigina and the Polymastigina. Senn (1900) distributed these colorless forms 

 among the three groups Pantostomatineae, Protostomatineae, and Distomati- 

 neae. As mentioned above, some of these organisms (e.g., members of the Mona- 

 daceae and Oicomonadaceae) have been shown to be colorless Chrysophyceae. 

 The systematic position of the majority of the forms, however, is still uncertain. 

 Since at least some of them possess features that suggest an affinity with the 

 Chrysophyceae, the three groups recognized by Senn and many subsequent 

 authors are here appended to the Chrysophyceae. 



The history of these groups is briefly considered below. 

 Pantostomatineae: This group was established by Kent (1880-1881, pp. 211, 

 229, as Flagellata-Pantostomata) to embrace a heterogeneous assemblage of 

 flagellated organisms that engulf food by pseudopodia. Its present circiimscrip- 

 tion is that given by Senn (1900, pp. 110, 111). He assigned to it a number of 

 genera, belonging to the two families Holomastigaceae and Rhizomastigaceae, 

 which share certain features, especially the absence of a differentiated oral ap- 

 paratus, solid food being engulfed by pseudopodia that form at any point on the 

 cell surface. Since the time of Senn, treatments of the group have been given by 

 Lemmermann (1907-1910, 1914), Doflein (1928), Fritsch (1935) and Huber- 

 Pestalozzi (1941). The complex comprises only the two families assigned to 

 it by Senn. 



Family Holomastigaceae (Lauterborn) Senn (1900, p. 112) 

 Family Rhizomastigaceae Biitschli orth. mut. Senn (1900, p. 113) 



Protomastigineae: This group was established by Klebs (1892, p. 293) to 

 include a number of families characterized by the fact that food is taken in at 



