BIGELOW: EXPLOK^TIONS OF THE COAST WATERS. 329 



plankton of the Gulf of Maine. In summer it usually plays a very 

 subordinate role, except locally (e. g., Stations 10215, 10216); but in 

 May it not only occurred at every station where Ceratium was 

 present, but even rivalled the latter in numbers in the eastern part 

 of the Gulf (Stations 10270, 10272, 10273) ; and in September it was 

 about as numerous as Ceratium off Swan's Island, (Station 10317) and 

 near ]Matinicus Island (Station 10329). 



Among the other organisms which appear in the catches, Halo- 

 sphaera deserves special notice, because now recorded for the first 

 time from the Gulf of Maine. This pelagic alga was widely distrib- 

 uted over the Eastern Basin of the Gulf in May (Stations 10269, 10270, 

 10271, 10272, 10273) though nowhere abundant; and it occurred 

 locally off Mt. Desert in June (Stations 10284, 10286) ; at one Station 

 (10310) in August. It was likewise found across the whole breadth 

 of the continental shelf, south of Nova Scotia, in June (Stations 10291, 

 10293, 10294, 10296) and off Shelburne in September (Station 10313). 



Halosphaera being widely distributed over the North Atlantic, 

 (Ostenfeld, 1910), and common at Canso, Nova Scotia, in summer 

 (Wright, 1907), was to be expected in the Gulf waters; it may have been 

 overlooked in the hauls of earlier years. So far as our few records go 

 they suggest that it is at its maximum in our Gulf in May, practically 

 disappearing during the summer, which parallels its seasonal occur- 

 rence in the North Sea (Ostenfeld, 1910).^ 



Tintinnids (Cyttarocylis) are apparently never an important 

 constituent of the plankton of the Gulf; though the records for 1914 

 and 1915 (so far detected at Stations 10271, 10272, 10276, 10298, 

 10304, 10310, 10317, 10318, 10319 in 1915) show that they may be 

 expected anv'^'here there. But they sometimes appear in large 

 numbers in the cold water along the south coast of Nova Scotia 

 (Stations 10233, 10234, 10236, 10237, 10242; Wright, 1907). The 

 northern distribution of this genus, and the fact that some forms are 

 characteristically neritic, others oceanic, (Brandt, 1910), lends in- 

 terest to them. But so numerous and so closely allied are the races, 

 or species (Jjzirgensen, 1899) that they must be left to the specialist. 



I For an account of the biology of Halosphaera in the Norwegian Sea see Gran, 1902, p. 12. 



