124 The Mastigophora 



of the external cytoplasm is drawn into the cyst before the pore is plugged. 

 Binucleate cysts, described in Dinobryon divergens (Fig. 4. 7, D-F), appar- 

 ently are the result of nuclear division just before encystment (92). The 

 mature cyst (Fig. 4. 7) is approximately spherical, but the external appear- 



Fig. 4.6. A-C. Myxochrysis pnradoxa; flagellate phase (B) and stages in 

 development of the plasniodiuni; xI6()0 (after Pascher). D-F. Kremastochrysis 

 pendens Pascher; non-flagellated forms suspended from the umbrella-like 

 float, and a flagellate stage; schematic (after P.) G. Formation of slender 

 pseudopodia in Dinobryon sertularia; diagrammatic (after Pascher). H. Gleo- 

 cystis-stage in D. sertularia; diagrainmatic (after Pascher). 



ance varies with the presence or absence of surface decorations and a 

 collar around the pore. 



Following suggestions of Pascher (214), five suborders may be recog- 

 nized: Euchrysomonadina, with a dominant flagellate stage; Silicoflagel- 

 lina, with a siliceous skeleton; Coccolithina, with a peripheral zone of 

 coccoliths; Rhizochrysodina, with a dominant amoeboid or plasmodial 

 stage; Chrysocapsina, with a dominant palmella. 



