INVERTEBRATE BOTTOM FAUNA 



541 



Fig. 384. 

 Deima fastosum, Th^el. " Michael Sars, 

 Station 48. 



tarda, Pontophilus norvegicus, Pagurus pubescens, Calocaris macandrece, 

 Geryon tridens. Worms : ApJwodite aculeata, Lcetnionice filicornisy 

 Lumbrinereis fragilis. Brachi- 

 opod : Waldheiniia septata (in 

 large quantities). 



This list also might 

 easily be extended. We 

 see, therefore, that the 

 fauna in the continental 

 (archibenthal) deep - sea 

 area of the Northern At- 

 lantic consists partly of 

 species peculiar to it, and 

 partly of others that regu- 

 larly belong to the con- 

 tinental deep-sea fauna of 

 the Norwegian Sea. Two 

 questions arise : How is 

 the Atlantic archibenthal 

 (and abyssal) fauna distri- 

 buted outside the Nor- 

 wegian Sea.'^ Is there any real resemblance between this fauna 



and its counterpart 

 in the cold area of 

 the Norwegian 

 Sea? 



There seem to Limits of the 

 be some reasons for ^^j;;^^'"'^"' 

 fixing the lower 

 limit of the archi- 

 benthal fauna at 

 about 2000 metres, 

 and the upper limit 

 at about 800 or 

 _ ^ 1000 metres. The 



^jt^ \| \| V V - charts of the area 



's^^^^l^Sr south of the ridges 



Kj^ published by the 



Danish " Ingolf " 

 Expedition show 

 that beyond 2000 

 metres the slope of the bottom becomes less steep downwards 

 to the vast abyssal plain whose upper limit may be put some- 



j^-M^jV"^^ 



Fig. 385. 



Peniagone tvyvillii, Thfel. " Michael Sars," 1910, Station 53, 

 2615 to 2865 metres. 



