The Mastigophora 155 



Family 3. Haematococcidae. The outer membrane is separated from 

 the periplast by a thick layer of "gelatinous material" into which extend 

 cytoplasmic processes. These features have been considered adequate 

 grounds for separating the family from the Chlamydomonadidae (260). 

 The Haematococcidae include Haematococcus Agardh (76; Fig. 4, 29, 

 H) and Stephanosphaera Cohn (256; Fig. 4. 29, F, G). 



Family 4. Phacotidae. The rather rigid membrane is often impregnated 



Fig. 4. 29. A, B. Dysinorphococcus variabilis Takeda, surface view and 

 median optical section; xl200 (after Bold). C-E. Pteromonas anguJosa Lem- 

 mermann, edge view, broad side, and outline in cross-section; xlOOO approx. 

 (after Pascher). F, G. Stephanosphaera pluvialis Cohn, colony and young stage; 

 diameter of colony reaches 50-60/x; diagrammatic (after Pascher). H. Haeyna- 

 tococcus pluvialis Flotow em. Wille, large flagellate stage; xl500 (after 

 Elliott). 



with calcium or iron compounds and possibly contains little or no cellu- 

 lose. A bivalve membrane (or "shell"), which does not fit the enclosed 

 organism very closely, is present in at least some genera. Fission occurs 

 within the membrane. 



The family includes the following genera: Cephalomonas Higinbotham (104), Coc- 

 comonas Stein (206), Dysinorphococcus (23; Fig. 4. 29, A, B), Pedinopera Pascher (206), 

 Phacotus Perty (206, 207), Pteromonas Seligo (174, 206; Fig. 4. 29, C-E), Thoracomonas 

 Skvortzow (206, 217), Wislouchiella (207). 



Family 5. Spondylomoridae. The membranes of the individual flagel- 

 lates are thin and the colony is not held together by a matrix. The larger 



