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BULLETIN OF THE BUREAU OF FISHERIES 



by the early spring of 1920, which corroborates Alexander Agassiz's suggestion that 

 Pleurobrachia abandons the surface in the cold season. 



Catches of Pleurobrachia in 1920 1 



' Forrecordsof Pleurobrachia from 1912 to 1916 see Bigelow, 1914, p. 126; 1914a, p. 402; 1915, pp. 318and 320; 1917, pp. 303 and 

 304; 1922, p. 158. In the winter of 1920-21 it was taken at stations 10488, 10491, 10492, 10497, and 10501. 



In most cases surface hauls alone would not have revealed the existence of the 

 local swarms of Pleurobrachia at these stations, but occasionally they are evenly 

 distributed downward through the upper 30 meters or so of water in the cold season, 

 just as they often are in summer. On the other hand, this ctenophore seldom or 

 never sinks into the deepest strata of the gulf, a statement justified by its absence 

 over the basins as well as by the fact that most of our records and all the richest 

 catches have been from hauls no deeper than 30 to 50 meters. 



Since Pleurobrachia is present in the Gulf of Maine throughout the year, it 

 necessarily experiences a wide range of temperature and salinity there. On the one 



