152 The Mastigophora 



cytoplasm. In the "haematocyst" of Haematococcus phivialis (76), the 

 pigment may completely mask the chromatophore. 



The order may be divided into four families of solitary types and two 

 of colonial genera. Among the solitary types, a typical cellulose mem- 

 brane is lacking in the Polyblepharidae, present in the Chlamydomonadi- 

 dae, and is replaced by a calcified bivalve "shell" in the Phacotidae. In 

 the Haematococcidae cytoplasmic processes extend into the thick mem- 

 brane. Colonial genera with a well developed matrix are assigned to the 

 Volvocidae; those without a matrix, to the Spondylomoridae. The order 

 has been surveyed by Pascher (206). 



Family 1. Polyblepharidae. These are typically solitary types with 

 somewhat flexible bodies. The genus Raciborskiella (Fig. 4. 27, C) is ex- 

 ceptional in that 4-8 flagellates may remain attached posteriorly to form 

 simple aggregates (colonies?). Flagellar numbers of 1, 3, 4, 5, 6, and 8 

 have been reported, but there are usually two or four. Binary fission 

 occurs in the flagellate stage, and the old flagella are usually inherited 

 by the daughter organisms. 



Chlorophyll-bearing species are included in the following genera: BipecUnomonas 

 Carter (31), Diuialiella Teodoresco (227), Hetcromastix Korshikov (31), Korschikoffia 

 Pascher (206), Mesostiginn Laiiterborn (206; Fig. 4. 27, D), Pedinomoiias Korshikov 

 (206), Phyllocardium Korshikov (162), Pocillomonas Steinecke (206). Polyblepharides 

 Dangeard {2d&), Pyramimouas Schm^rda. (Pyramidomonas Stein) (23,31,89,217; Fig. 4. 



27, J), Raciborskiella Wislouch (206; Fig. 4. 27, C), Spennatozopsis Korshikov (2^)6). 

 TrichJoris ScherfFel and Pascher (206; Fig. 4. 27, K), and Tetrachlnris Pascher and 

 Jahoda (227) with four flagella. Chromatophores are lacking in Furcilla Stokes (206) 

 and Polytomella Aragao (128, 206; Fig. 4. 27, F-I). Cytological descriptions are avail- 

 able for Pyramimonas (25, 89) and Polytomella (128). 



Collodictyon Carter (244; Fig. 4. 27, A, B) is sometimes included in this family. How- 

 ever, the plastic body, the longitudinal groove, the development of pseudopodia, and 

 the lack of information on stored reserves cast doubt upon the validity of such an 

 assignment. 



a 



Family JC Chlamydomonadidae. There is a well-developed membrane, 

 within which fission results in two or more daughter organisms (Fig. 4. 



28, A, B). In Chlamydomonas nasuta (129), the plane of the first fission 

 is perpendicular to the long axis of the body. Prior to fission, the or- 

 ganism either rotates within its membrane through an arc of 90°, or else 

 the chromatophore and nucleus change their positions accordingly (Fig. 

 4. 28, C, D). The plane of the second fission is perpendicular to that of 

 the first. In various species, adhesion of the membranes of adjacent or- 

 ganisms often produces large palmellar aggregates or sheets, especially 

 during growth on a solid medium. 



The following genera contain chlorophyll-bearing species: Apiococcus Korshikov 

 (206), Brachiomonas Bohlin (206; Fig. 4. 28, F), Carteria Diesing (23, 206, 217; Fig. 4. 

 28, O), Characiochloris Pascher (206), Chlawydonwnas Ehrenberg (94, 206, 217; Fig. 

 4. 28, C, D, G). Chlorobrachis Korshikov (206.' 256), Chloroceras Schiller (207), Chloro- 

 goniuin Ehrenberg (206; Fig. 4. 26, E), Clilornphysema Pascher (206), Diplostauron 



