120 



bulletin: museum of comparative zoology. 



salinity 32.6% . 

 salinity about 32.5%<> 



salinity about 32.6% . 



salinity about 32.9%o. 



only some twenty miles from land; and so many off-shore hauls were 

 made (e. g., Stations 23, 24, 27, 28, 29, 30, 31) that its absence from the 

 more nearly oceanic part of the Gulf can hardly be laid to an accidental 

 failure to capture specimens. It was not found in the northeastern 

 part of the Gulf, nor in the Grand Manan Channel (Stations 33, 34, 

 35, 36, 37) ; but its absence from the latter is probably associated with 

 the general poverty of the zooplankton in that region. It was taken 

 three times in the closing net, at 30 fathoms (Stations 22, 25), and 

 20 fathoms (Station 19), and once on the surface (Station 32). Proba- 

 bly it would have been found oftener at the latter horizon had we 

 made more surface hauls near shore, especially at night. But as it 

 happened, most of the night hauls were made far off shore, where 

 Clione was not found. The hauls afford the following data on tem- 

 perature and salinity: — 



Station 2 30 fathoms temperature 41.5° 

 Station 19 20 fathoms temperature about 



47° 

 Station 22 30 fathoms temperature about 



46.5° 

 Station 25 30 fathoms temperature about 



48.5° 

 Station 32 surface temperature 57° salinity 32.5%o. 



The salinity ranges from 32.5-32.9%o> the temperature from 41.5° 

 to 57°; and at all other stations where Clione was taken, the nets, 

 in their course, passed through waters with physical characters lying 

 within these limits. In the Gulf, adult Clione occurs over a wide 

 range of salinity and temperature, in water fully 10° warmer than the 

 Labrador Current. But our collections throw no light on the condi- 

 tions under which it reproduces. 



Limacina balea (Plate 5) . — The occurrence of this pteropod was 

 even more circumscribed than that of Clione limacina. It was taken 

 at Stations 19, 22, 23, 24, 25, 30, 40, i. e., in two general regions, first 

 in the northwest corner of the Gulf, off Casco Bay and over the deep 

 trench beyond Piatt's Bank and Jeffrey's Bank, and second, on 

 German Bank. The known salinities and temperatures of the 

 captures are: — 



Station 19 25 fathoms closing-net temperature 47° salinity 32 . 5%o 

 Station 25 30 fathoms closing net temperature salinity 32.9%o 



about 48° 

 Station 30 surface temperature salinity 32.7%o 



about 52° 



