I&2 
F. Cavers. 
The Gymnodiniaceae (Pig. 9) may well have arisen from a 
Cryptomonad like Protochrysis, with two unequal flagella arising 
from a lateral depression having the form of an incomplete trans¬ 
verse groove. In the Gymnodiniaceae, however, there are numerous 
chromatophores instead of two, and the nucleus, as pointed out by 
Klebs (68) has a characteristic fibrillar structure apparently not 
found in the Chrysomonadineae. But granting these differences, 
and the absence of what may be strictly regarded as transitional 
Fig. 9. Gymnodiniaceae. —1, Hemidinium nasutum Stein, showing flagellum 
grooves, flagella, nucleus, and numerous small chromatophores. 2, Gymno- 
dinium bogoriense Klebs. 3 to 8, Gymnodinium votundatum Klebs: 1, two cysts 
enclosed in the membrane of the parent cell ; 2, rupture of cyst shown on the 
left in preceding figure, to set free the two motile cells ; 5, motile cell; 6, the 
