AN UNUSUAL OCCURRENCE OF DINOFLAGEL- 
LATA ON THE CALIFORNIA COAST. 
HARRY BEAL TORREY. 
DiscoLorations of the sea due to the presence of minute 
organisms, and often many miles in extent, have been seen in 
various parts of the world, along the shore and in the open sea. 
Deep-water sailors are familiar with such appearances, which 
they call * whale food," or “brim.” The cause of the color is 
not always the same organism, though perhaps most frequently 
some species of Dinoflagellata, in enormous numbers. 
This phenomenon was observed at San Pedro, Cal. during 
the present summer, and, according to the testimony of old 
residents, for the first time in that region. Something of the 
sort is said to have been noticed in Tomales Bay, some five 
hundred miles farther northward, in the early seventies. These 
are, I believe, the only known instances of its occurrence on 
the California coast; so.that its rarity alone seems to demand 
a recording of the few notes taken. during this last appearance. 
It was first noticed on July 7 as a red streak off the mouth 
of San Pedro Harbor. During the next few days it approached 
the shore, changing its shape and dividing into several patches, 
each many acres in extent. On the 16th it reached the shore, 
and was the cause of a most unusual display of phosphorescence, 
which reappeared many evenings in succession... The phosphor- 
escent water was found to contain vast numbers of a peridinian 
which I have referred tentatively to the genus Gonyaulax (see 
description below), and which gave it its red color during the 
day. Under the microscope Gonyaulax responded with a flash 
of light to any marked disturbance. of the water. containing it. 
At this time Noctiluca, so abundant later on, was not noticed. 
Wherever the ocean waters were roughened the wavelets were 
crested with green-blue light. In the quiet waters of the harbor 
the fishes, pelagic worms, and crustaceans traced trails of fire. 
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