PLANKTON OF THE WOODS HOLE REGION 
93 
Mass. From June 22, 1922, until May 1, 1923, observations were made daily at 
the same spot where all my previous material had been taken. Fortunately a 
series of collections had been made by E. A. Goffin during the spring of 1922. From 
these I was able to trace the first appearance of the summer species. From May 1 
to December 1, 1923, the collections were made three times a week, except during 
the interval from August 22 to October 4. The records for the past summer are 
therefore not as complete as those of 1922, although they serve as a basis for com- 
parison. 
A kind invitation from Dr. P. S. Galtsoff to assist him in his monthly surveys of 
Long Island Sound from September, 1922, to August, 1923, made possible valuable 
observations on the distribution of certain pelagic organisms, particularly the 
diatoms, in relation to their presence at Woods Hole. 
It is a pleasure to express my especial gratitude to Prof. A. D. Mead and Prof. 
K. M. Field, of Brown University, who furnished me helpful assistance and guidance 
throughout my work. I am especially indebted to Marie D. P. Fish for her careful 
tabulation of Vinal N. Edwards's records of surface collections and temperatures 
collected over a period of 15 years. I am indebted to Dr. P. S. Galtsoff, who made 
possible my observations on salinity at Woods Hole and the plankton of adjacent 
regions, and I wish also to express thanks to Dr. Henry B. Bigelow, Dr. Hugh M. 
Smith, Dr. Paul Bartsch, Dr. Albert Mann, and Prof. A. E. Verrill, for helpful 
advice and criticism rendered at various times during the progress of my work. 
METHODS 
My first plans provided for daily observations on temperature of the air and 
water (surface and bottom), salinity, oxygen, wind, weather, sea, transparency, 
vertical hauls, and surface and bottom collections with plankton nets of No. 2 
and No. 20 bolting cloth. Because of the amount of time required to identify 
the many species of zooplankton and phytoplankton it was found desirable to 
discontinue certain of these observations. The following schedule was finally 
adopted: 
1. Daily temperatures of surface water and air. 
2. Salinity (at certain periods) and density. 
3. Daily meteorologic observations on wind, weather, sea, etc. 
4. Vertical hauls at weekly intervals with No. 20 net. 
5. Daily surface hauls with No. 2 and No. 20 nets. (Later, No. 20-net hauls 
were reduced to twice a week except during the diatom maxima.) Nets 3 feet by 
12 inches with a brass bayonet-lock bucket on bottom were used. 
The temperature was taken each day at the time of setting the plankton nets. 
A series of observations later proved conclusively that at all times the bottom 
temperature at my station is exactly the same as that of the surface (Table 2, p. 101). 
Bottom observations then were made only during periods of rapidly declining or 
rising temperatures. 
For a period extending over four months salinity was determined daily by 
titration with nitrate of silver. When these could not be made at once, they were 
preserved in the standard "citrate of magnesia" bottles of the sort used for that 
