f>APENFUSS: CLASSIFICATION OF THE ALGAE 155 



Senn (1900, pp. 170-173) maintained the chloromonads as a separate group 

 in the Flagellata and gave a systematic treatment of the complex. Some of the 

 genera wliich he referred to the group have since been shown to belong else- 

 where. Since the time of Senn, Lemmermann (1907-1910), Pascher (1913c), 

 Skuja (1948) and Huber-Pestalozzi (1950) have given systematic treatments 

 of various genera comprising the complex, and Drouet and Cohen (1935, 1937) 

 have given a good account of the morphology of Gonyostomum semen. Fritsch 

 {in West, 1927, p. 405) elevated the group to the rank of class. 



The majority of authors have regarded the Chloromonadophyccae as an iso- 

 lated group of flagellates of uncertain relationship (cf. Fritsch, 1935, p. 723; 

 Smith, 1950, p. 625). Prescott (1951, p. 421) has in fact erected a phylum 

 Chloromonadophyta for the group. Oltmanns (1922a, p. 44) recognized the cor- 

 respondence between the chloromonads on the one hand and the euglenids and 

 the cryptomonads on the other, but made it clear that he like many others was 

 not sure that this implied a definite relationship. 



Both Skuja (1948) and Huber-Pestalozzi (1950, p. 2) place the Chloromo- 

 nadophyccae, Cryptophyceae, and Dinophyceae as classes in the phylum Pyrro- 

 phycophyta. The uniflagellate genus Monomastix shows relationships to both 

 the Chloromonadophyccae and the Cryptophyceae. Huber-Pestalozzi (1950, p. 

 2) considers it the type of a subclass in the Cryptophyceae whereas Skuja (1948, 

 p. 344) places it in the Chloromonadaceae. 



Although neither the Chloromonadophj^ceae nor the Cryptophyceae appear 

 to be closely related to the Dinophyceae (see the section on the Cryptophyceae 

 regarding Pringsheim's [1944] and Graham's [1951] doubts about the presumed 

 relationship between the Cryptophyceae and Dinophyceae) it is not inconceiv- 

 able that the Chloromonadophyccae and the Cryptophyceae are at least dis- 

 tantly allied and they are therefore here placed near each other as classes ap- 

 pended to the Pyrrophycophyta. Outstanding points of agreement between these 

 two classes are: (1) the cells are naked and more or less dorsiventral; (2) a 

 longitudinal furrow is present in the cells of both classes; (3) the majority of 

 the forms in both groups are anteriorly bifiagellate; (4) trichocysts are present 

 in certain members of both groups; (5) some chloromonads have a cavity at the 

 anterior end of the cell (connected to the exterior by a duct) which is com- 

 parable to the "gullet" of some cryptomonads. 



A conspicuous but phylogenetically perhaps insignificant difference between 

 the two groups is the storage of reserve food as starch or starchlike compounds 

 in the Cryptophyceae and as oil in the Chloromonadophyccae. The flagella in 

 the two groups are also of a somewhat different structure and are arranged 

 differently. 



The systematic arrangement here adopted is essentially that of Huber- 

 Pestalozzi (1950), except that Moyiomastix is considered, in agreement with Skuja 

 (1948), as belonging to the Chloromonadophyccae instead of the Cryptophyceae. 



Class Chloromonadophyceae (Klebs) Fritsch orth. mut. Drouet et Cohen (1935, p. 

 423) 



Syn.: Raphidophycinees Chadefaud (1950a. p. 789) 



Order MONOMASTIGALES (Huber-Pestalozzi) Papenfuss, stat. nov. 

 Syn.: Subclass Monomastiginae Huber-Pestalozzi (1950, p. 2) 

 Family Monomastigaceae Huber-Pestalozzi (1950, p. 2) 



