554 



BULLETIN OF THE BUREAU OF FISHERIES 



the western slope of the basin and in the sink off Cape Ann, highest (4° to 6°) in 

 the eastern side and in the Eastern Channel — the isotherms for AprU (fig. 25) do not 

 outline the warm indraft into the eastern side as clearly as do those for March 

 (fig. 13). 



Fig. 25.— Temperature at a depth of 100 meters, April 6 to 20, 1920. The shaded area was colder in April than in March 



Unfortunately the data do not afford an annual comparison for depths as great 

 as'l^tliis, no readings having been taken so deep in April, 1925; but temperatures of 

 2.7°ito 2.9° at 80 to 84 meters in Massachusetts Bay on April 21 to 23 of that year, 

 and of 2.9° at 91 meters at a station 8 miles off Little Duck Island (off Mount 



