384 



BULLETIN OF THE BUREAU OF FISHERIES 



sachusetts Bay, it is not likely that the vernal flowerings become active there until 

 after the middle of March — that is, at least three weeks later than in the waters be- 

 tween Cape Ann and Cape Elizabeth, or in Cape Cod Bay (p. 396). 



Fio. 104.— Distribution of the more characteristic types of phytoplankton, February to March, 1920. 1, rich diatom; 

 2, sparse diatom; 3, sparse Ceratium and diatom 



The shallow waters off western and southern Nova Scotia, out to and including 

 German and Browns Banks, are the site of a second center of propagation for dia- 

 toms late in March, for though the phytoplankton was still very scanty there on 



