ATLANT. DEEP-SEA EXPED. 1910, VOL. ill] 



BRACHIOPODA, LAMELLIBR. ETC. 



from year to year and from season to season. Similarly 

 genuine arctic species may be found in the frontier-zone 

 between the warm and cold areas. 



At station 102 two specimens of Cuthonella abyssi- 

 cola were taken, the one in the trawl from a depth of 

 1098 metres, the second in a large plankton townet with 

 1500 metres of wire out. The actual depth at which a 

 plankton-net is towed during a horizontal haul is com- 

 monly calculated at one-half of the length of wire out, 

 which in the present case works out at about 750 metres; 

 this would seem to indicate that one of the specimens of 

 Cuthonella abyssicola had been caught about 350 metres 

 above the bottom, but this conclusion is inadmissible, as 

 all other evidence goes to establish Cuthonella abyssicola 

 as a bottom species, the other specimen, like all those 

 previously recorded, having been obtained from the bot- 

 tom. If, on the other hand, the depth is calculated as 

 two-thirds to three-fourths of the length of wire paid out, 

 the net in question at st. 102 may have skimmed along 

 the bottom, and this would account for the capture of 

 bottom forms, for, in addition to Cuthonella abyssicola, 

 the net brought up three specimens of Nymphon grossl- 

 pes Bell *) and one of Boreonymphon robustum Bell 2 ), 

 which are well-marked bottom animals. 



1 ) 0rjan Olsen, Pycnogonida, Rep. Sci. Res. Michael Sars North 



Atlantic Deep Sea Exp. 1910, vol 3, part 1, 

 1913, p. 6. 



2 ) On this Boreonymphon robustum were attached two young 

 specimens of Scalp'ellum angustum G. O. Sars, one on the abdomen, 

 the other on the ventral side of the femur of the third left leg. The 

 largest specimen measured 45 mm. in length. This species is not 

 mentioned in Hoek's report on the Cirripedia from the "Michael Sars" 

 Expedition (Rep. vol 3, part 1). 



At st. 70, depth 1100 m., only plankton-nets were used. 

 The lowermost appliance, a young-fish trawl was towed 

 with 1700 metres of wire out. When hauled up it con- 

 tained numerous bottom invertebrates, mollusca, echino- 

 dermata, annelids etc. Here the actual depth was two- 

 thirds of the length of wire out. This conclusion agrees 

 with what was observed during the cruise of the "Armauer 

 Hansen" in may 1914. At stat 4, Lat. 62° 15' N., Long. 

 0° 15' E, a sounding immediately before lowering the 

 plankton-gear gave a depth of 830 metres, a second sounding 

 after hauling in the gear, 770 metres. The lowermost 

 appliance, a fry-net, was towed with 1200 metres of wire 

 paid out, and was found to be filled with mud, sand, 

 stones and different bottom animals (cfr. the paper by 

 the present author, cited on p. 4). In this case the actual 

 depth works out at about two-thirds of the length of wire 

 out. At station 3, Lat. 62° 10' N, Long. 0° 8' E, the lower- 

 most appliance with 2000 metres of wire out came up 

 with mud and bottom animals. No sounding was taken 

 at this station, but 20 miles in one direction the depth 

 was 1743 m., and 20 miles in the opposite direction 1060 

 metres. The depth may accordingly be computed at about 

 1400 metres (cfr. Jorgensen: Sternoptychidae(Argyropelecus 

 and Sternoptyx) 1 ). 



x ) Rep. Danish Oceanogr. Exp. 1908 — 10 to Mediterranean and 

 Adjacent Seas, vol. 2, Biol. A 2, 1915, p. 4. 



