Flagellata and Primitive Algce. 
r 1 7 
is attached to its substratum (usually an Eudoritta colony), by a 
long stalk dilated at the base, and has a thin periplast; while 
Dcrepyxis (Fig. 6, 2) resembles Chrysopyxis in having an outstanding 
perisarc with a projecting collar. Of the colonial forms, Syncrypta 
and Synura have globose motile coenobia, consisting of 16 to 64 
Fig. 6. ISOCHRYSIDALES (1 to 6) and OCHROMONADALES (7 to 16). —1, 
Hymenomonas roseola Stein. 2, Derepyxis dispar Stokes. 3, Stylochrysalis parasitica 
Stein (in 4, transverse division is shown). 5, Synura Uvella Erhb. 6, Syncrypta 
Volvox Erhb. 7, Ochromonas crenata Klebs. 8 to 10, Ochromonas mutabilis Klebs, 
showing migration of food vacuoles within the protoplasm and amoeboid changes 
of form of the cell. 11, 12, Cyclonexis annularis Stokes : in 11 the ccenobium is 
seen from the surface, in 12 from the side. 13 to 16, Dinobryott Sertularia Ehrb.: 
in 14 to 16, stages in division and perisarc formation. 
1, from Klebs ; 2, 11, 12, from Stokes; 3 to 6, from Stein ; 7 to 10, 14 to 
16, from Klebs; 13, from Senn. 
biflagellate individuals closely aggregated in a radial manner, their 
pointed hinder ends directed towards the centre of the coenohium ; 
in Syncrypta (Fig. 6, 6) the cells have a thin periplast and the 
