18 Sigurd Johnsen. 
away by currents and found to occur in water and at depths 
not originally native to them. 
The range of temperature and salinity of the species in 
northern waters can not be established as the depth of capture 
is unknown in most cases. All records are, however, from 
localities influenced by the warm and salt Atlantic water (Gulf 
Stream). This is evident from comparison of the accompanying 
chart of distribution with fig. 1 showing the currents of the Nor- 
wegian Sea. The richest captures are from places where this 
water occupies layers”of a considerable vertical extent, namely 
the southern part of the Norwegian Sea and the fjords of Western 
Norway’). 
The occurrence in the northern latitudes of Atlantic forms 
among the fishes generally has been looked upon as a result of 
the Gulf Stream, the specimens having drifted northwards with 
the current. In a special paper (1911, in Norwegian) I have 
advocated a somewhat different view. It is obvious that the 
distribution of the Atlantic forms in the Norwegian Sea and along 
the coast of Norway must coincide with or fall within the distri- 
bution of the Atlantic water, but to seek the cause of their 
occurrence in the mechanical effect of the current is too hasty an 
1) The hydrographical conditions along a section through the Norwegian 
Sea from the mouth of the Sognefjord and to the west are shown by the figs. 165, 
187 and 188 in a chapter on Physical Oceanography by Helland-Hansen 
in Hjort & Murray (1912). The cruise of the “Armauer Hansen” in 1914 
corresponds nearly to this section. On the station 3 where at night a net 
with 200 m. wire out (depth of gear abt. 100—130 m.) had captured 7 spe- 
cimens of M. glaciale (see p. 10) the temperatures of the two nearest hydrogra- 
phical stations were as follows in Centigrades: Surface: 7.2 and 8.0; 100 m.: 
6.3 and 8.0; 200 m.: 3.6 and 6.5; 400 m.: 0.47 and 2.6; negative temperatures 
irom 600 metres. 
The following hydrographical data are from the Sognefjord off Vangsnes 
in August 1916. This station corresponds to the station 4 of the *Armauer 
Hansen” 1914 where one M. glaciale was caught in net with 600 m. wire 
(depth abt. 400 m.) and another specimen in net 1200 m. wire (abt. 800 m. 
depth). (See p. 5). Temperatures in Centigrades and salinity per thousand: 
Om., 15.18”, 4.56; 5 m. 12.37* 24.34; 50 m., 6.03*, 34.08; 100 m., 6.66”, 34.74; 
300 m., 6.73", 34.97; 600 m., 6.71”, 35.00; 1000 m., 6.69”, 35.00. (The hydro- 
graphical data enumerated here are from observations by Professor Helland- 
Hansen). 
