58 bulletin: museum of comparative zoology. 



twelve to forty-two fathoms; that for 52° from about five to about 

 twenty-five fathoms. The curve for 54°, however, runs parallel with 

 the surface. But the course of the curves eastward from Station 31 

 shows that the warm water does not extend to the coast bank. On the 

 contrary, the curve of 50° rises sharply until at Station 29 our serial 

 observations locate it at a depth of only about three fathoms. The 

 warm water at Station 31 can be further delimited by a profile across 

 the mouth of the Bay of Fundy (Stations 33, 36, 31, 29, fig. 18) which 

 shows that Station 31 is warmer at corresponding depths than either 

 of the other three, Station 33 practically reproducing Station 29, ex- 

 cept that the immediate surface was about .5° warmer. Evidently 

 then there was a mass of water lenticular in section, several degrees 

 warmer, at all depths, than the water either east, north, or west of it, 

 at Station 31. Whether this warm area was circumscribed on the 

 south also, or whether it was continuous with the warm off-shore water, 

 possibly even with the Gulf Stream water, which washes the conti- 

 nental slope, is doubtful. 



The profiles show that the temperature conditions over Jeffrey's 

 Bank, on German Bank, and off the mouth of the Grand Manan 

 Channel are closely related to one another, differing correspondingly 

 from the deeper adjacent waters, in being colder at the surface, warmer 

 at the bottom. The three differ from each other, it is true, in degree, 

 but not in kind. But a profile running southeasterly from Mt. Desert 

 for about fifty miles to Station 28 (Stations 37, 32, 28, fig. 19) shows 

 that there is no spreading of the curves on the slope here, which is 

 probably due to the fact that Station 37 lay in the shallow, partially 

 enclosed waters of Frenchman's Bay, where local seasonal warming 

 no doubt played a greater part than it does further off shore. But a 

 profile running off shore from the mouth of Casco Bay (Station 15) 

 to Station 24 shows a spreading of the curves at the shore end (fig. 20) 

 and a profile from Swan Island (Station 38) to the deep basin near 

 Piatt's Bank roughly parallel in direction to the above, shows much 

 the same temperature conditions, with the difference that at the 

 northerly end, which lies just east of the main entrance to Penobscot 

 Bay, the spreading of the curves is more extreme than it is further 

 west. 



Seasonal changes in Massachusetts Bay. — Our work over the central 

 and northeastern parts of the Gulf did not last long enough to show 

 anything about seasonal changes, further than that the bottom temper- 

 ature at Station 41 (40.3°) compared with what we found off Cape Ann 

 and in the trench west of Jeffrey's Ledge at the beginning of the trip^ 



