Ad. s. Jensen: The Selachians of Greenland. 39 



no temperature observations were made in it, but in two adjacent fjords (Sermilik 

 east of Sermersok and Lichtenau Fjord) bottom-temperatures of respectively — 0.4° 

 and 0.6° C. were found; thus, an arctic-abyssal species like R. hyperborea would easily 

 be able to live in such a fjord. 



Turning now from such a distinctly cold-water form like Raja hyperborea to the 

 other Selachians occurring at West Greenland, we find among them some which in 

 the sea between Greenland and Europe only occur inside the line forming the boun- 

 dary between the two kinds of bottom-water. These species are Raja fyllae, Raja 

 lintea and Centroscyllium Fabricii. As is seen clearly and distinctly from the Chart 

 (fig. 12), these occur with respect to the hydrographic boundary line mentioned only 

 on the opposite side to R. hyperborea. They may, as is the case with Raja fyllae, 

 go almost as far north as R. hyperborea, right up to the west side of Spitsbergen, 

 but they keep constantly to that part of the sea-bottom where the temperature is 

 positive (ca. 3° C. and above), the so-called "warm area" of the Northern Ocean. 



In good agreement with this these warm-water forms occur at West Greenland 

 only in that part of the deep Davis Strait which lies south of the submarine ridge 

 between Baffins Land and Greenland (cf. Chart fig. 12). They go right to the top 

 of the ridge, but not beyond it. 



But along with this occurrence in the warm water of the Davis Strait some of 

 these species have still another, as they have been taken by the "Tjalfe" Expedi- 

 tion in the fjord region of the northern part of the Julianehaab district, namely in 

 Brede Fjord and Skov Fjord. This is the case with Centroscyllium Fabricii and 

 Raja spinicauda, the latter having been taken on the Atlantic side of the ridge 

 in the Davis Strait (and undoubtedly will also be found in future at other piaces 

 in the Atlantic). The reason for the occurrence of these Selachians in the West 

 Greenland fjords mentioned is, that their hydrographical conditions, so far as the 

 deeper water-layers are concerned, agree precisely with those obtaining in the 

 Southern Davis Strait, as will be seen from a comparison of the following tempera- 

 ture observations: 



