NO. 4 ALLEN: PLANKTON DIATOMS 57 



3. The Gulf of California supports essentially the same forms of 

 phytoplankton as are found in the neighboring ocean. 



4. There is some indication that production is better near islands 

 in the Gulf of California, but there was one notable exception. 



5. The occurrence of one species in nearly pure culture in mid- 

 Gulf suggests the possibility of influences especially favorable to it. 



6. Satisfactory explanations of some of the phenomena of occur- 

 rence of plankton diatoms in the Gulf of California can not be given 

 until thorough studies are made of physical, chemical, meteorologi- 

 cal, and general biological conditions there. 



