No. 423.] OCCURRENCE OF DINOFLAGELLATA. 189 
have been in this instance some distance from the beach, but 
also because it has never before been reported from San Pedro. 
The Gonyaulax served here as a means of discovery. 
The above facts have been enumerated because they exhibit 
in a striking way a natural cause in process of eliminating the 
unfit of several and diverse species, which are resisting with 
various degrees of persistence and success. Whether this elimi- 
nation is promiscuous, or correlated with variation from the type 


Fic. 1. - Beach covered with dead animals, mainly holothurians with several selachians in 
T 

of the species, is a question for whose solution material has been 
collected by Dr. F. W. Bancroft of this laboratory. 
The “red water" occurred for two hundred miles at least 
along the coast, from the region of Santa Barbara to San Diego, 
and extended several miles to'sea. It was still present around 
San Pedro on September r. Wherever it was seen the fisher- 
men reported a scarcity of food fishes. The small harbor fishes 
seemed to be unaffected by: it, and the tiny invertebrates of the 
plankton were abundant in it. - Noctiluca appeared in great 
numbers toward the end of July, and devoured Gonyaulax with 
