CHAP, ix.] THE DEEP-SEA FAUNA. 463 



I have already pointed out that in reasoning upon 

 the ground of identity of deep-sea forms with species 

 hitherto found in Scandinavia, we must rememher 

 that the conditions of temperature of our southern 

 seas at great depths the conditions which appear to 

 have the greatest influence upon the distribution of 

 species correspond very closely with those of much 

 shallower water in the Scandinavian seas ; and that 

 consequently the corresponding fauna in the northern 

 regions was much earlier, and is still much better 

 known. Mr. Gwyn Jeffreys lays great stress upon 

 the greater numbers and the greater development 

 in size and in prominent characters of sculpture and 

 other ornament, of the Arctic examples of species 

 common to our deep water. This is no doubt often 

 the case, but we must admit that in many groups, 

 and particularly among the mollusca, there is a 

 tendency to dwarfing in deep water, and I should 

 think it very possible that a species may attain 

 a greater size and development in that region where 

 its zone of special temperature conditions comes 

 nearest the surface, most under the influence of 

 air and light. 



Many of the mollusca from the deep water have 

 hitherto been found only in the northern portions of 

 the area examined, and are generally allied to northern 

 forms. As examples of this group I may mention 

 two interesting additions to the already famous Shet 

 land fauna, Buccinopsis striata, JEFFREYS (Eig. 76), 

 a form somewhat allied to Buccinopsis dalei, which 

 has long been one of the prizes of the Shetland seas, 

 and Latirus albus, JEFFREYS (Eig. 77), known also 

 from the coast of Norway. Cerithium granosum, S. 



