No. 423.] OCCURRENCE OF DINOFLAGELLATA. IQI 
some twenty miles to sea. And if this were so, the cause of 
the rapid reproduction would still remain obscure. 
The boundaries of the red streaks were quite sharply marked, 
although the water between streaks often contained Gonyaulax 
in abundance. Temperatures and determinations of salinity 
were taken at the surface and at the bottom of both red 
streaks and water entirely free of Gonyaulax. The. readings 
averaged the same in all cases for the same depths. Soundings 
with a rather crude water bucket indicated that Gonyaulax was 
present approximately in as great abundance at the bottom at 
the depth of six fathoms as at the surface. 
The key to the problem lies, I believe, in the chemical consti- 
tution of the water, since, aside from a sensitiveness to chemical 

Fic. 3. 

Fic, 2. Gonyau lax, showing both 
Fic. 3. — Gonyaulax from upper cg sou arrangement of anterior plates. 
stimuli which.'it possesses in common with all living things, 
Gonyaulax is holophytic, if its color is a safe criterion. Zumstein 
has recently shown that the chlorophyll-bearing Euglena may lose 
its color under appropriate conditions and change its method of 
feeding in consequence to the saprophytic type. The C. michae- 
lis and Polykrikos sf., as well as the Peridium (?) swarmspore, 
found with Gonyaulax, were colorless. Not only, then, within the 
limits of one family of protophytes do two methods of nutri- 
tion exist, but in a single species, and possibly in a single 
life cycle. But the question of the source of the food of marine 
organisms is too vast a subject to:be attacked with the scanty 
materials at hand. Whether- Gonyaulax is nourished by inor- 
ganic or organic solutions, and whether a variation in food supply 
is the explanation for its unusual abundance, are problems to be 
solved by future experiment. 
