yo NORMAN: ON THE MOLLUSCA OF BERGEN FIORDS. 



the Bergen Faunae is very nearly the same. A marked difference 

 however shows itself when we come to examine what are the 

 species which are present in the one Fauna but absent from the 

 other. The Shetland moUusca which do not occur at Bergen are 

 almost all European forms, inhabitants of warmer water than 

 that which is usually to be met with in the Norwegian Fiords; 

 while most of the mollusca marked Polar (P) are perhaps such as 

 might rather be called abyssal, though they occur in as shallow 

 water as 50 fathoms at times. They are mollusca which, though 

 living on a rather soft (Foraminiferal and gritty) bottom, do not 

 like mud such as that of the Bergen Fiords, and we should 

 not expect to find them there; but they are almost sure to be 

 found hereafter outside the islands which fringe the Bergen coast. 

 On the other hand, among the Bergen mollusca unknown 

 near Shetland there are a few European but many Polar species, 

 while the larger number are abyssal forms which are scarcely 

 likely to be found in the shallower sea at Shetland. Though the 

 deepest water of the British Seas is that round Shetland, yet it 

 never exceeds 170 fathoms,* and the bottom is not that fine mud 

 which these abyssal mollusca of the Bergen Fiords delight in. 

 Further out in the Atlantic, however, to the west of Shetland, 

 where the conditions are favorable to their existance, they reap- 

 pear, and for the most part have a wide distribution in the depths 

 of the sea, several reaching to the Mediterranean on the one hand 

 or to Davis' Strait on the other. 



MOLLUSCA OF DENMARK. 



Out of the 190 Testaceous Mollusca of Denmark, 22 are 

 unknown at Bergen. Only one Polar species crops up among these; 

 the rest are almost without exception European. The Fauna of 



* The "Outer Haaf" is usually 80 to no fathoniy. It is only 25 — 30 

 N. by W. of Unst that the depth of 170 was reached in our dredgings. 



IJ.C, ii., i\Iar., 187 



