588 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



Salinity. Mr. G. Gorbunow found the salinity range in the North Kara Sea to be 

 from 34.47 to 34.99 per thousand. A record of 37.01 per thousand at Lomonossow 

 station 71 is apparently an error. He said that the salinity of the different layers in the 

 vicinity of Franz Joseph Land seemed to play absolutely no part in the distribution 

 of the echinoderms, though the fresher water that may be found in the higher layers 

 may be of significance for this species, also Korethraster hispidus and Ophiopus arcticus. 



Occurrence. Like the other Arctic comatulid Heliometra glacialis, this species 

 frequent!}" occurs in dense masses, completely carpeting the sea bottom. It was extraor- 

 dinarily abundant at Danmark station 99 off eastern Greenland, at Ingolf station 

 116 south of Jan Mayen, at Thor station 52, Ingolf station 124, and Michael Sars 

 station 10 (1900) all northeast and east of Iceland, at Michael Sars station 55 (1902) 

 northeast of the Faroes, at Vtfringen station 312 west of Bear Island, at Vfiringen stations 

 343 and 362 west of Spitzbergen, and at Sedow station 57 in the north Kara Sea. It 

 was also found abundantly about eastern Spitzbergen by the Helgoland. These locali- 

 ties range in depth from 185 to 1358 meters, and in temperature from 1.24 to 

 0.40 C. It was common and possibly abundant at Thor station 51 off northeastern 

 Iceland, Ingolj station 143 north of the Faroe Islands, Vfringen station 18 northeast 

 of the Shetlands, Vfiringen station 286 southwest of Bear Island, V0ringen stations 

 359 and 337 off western Spitzbergen, and Yermak (Jermak) station 76(10) north of 

 Nova Zembla. The depth at these stations varied between 37 and 817 meters, 

 and the temperature ranged from 1.20 to +0.80 C. Apparently, therefore, this 

 species thrives best in the deeper and colder portions of its habitat. The average 

 temperature of the habitat is considerably lower in the eastern than in the western 

 portion of the range. 



Although occurring in relatively shallow water, this species is essentially an inhabi- 

 tant of the open sea and does not enter gulfs or fjords. The only partially enclosed 

 waters from which it is known are the Aberdare Channel in the Franz Joseph archi- 

 pelago, Discovery Bay in Grinnell Land, Inglefield Gulf and Murchison Sound in 

 northwestern Greenland (there is some doubt regarding this record), and the Ice 

 Fjord, Spitzbergen, where it was dredged by the Vfiringen, though Prof, von Hofsten 

 in his detailed survey of that region failed to find it. Gorbunow says that this species 

 is very widely, though patchily, distributed in the northern half of the Kara Sea, 

 occurring in great quantities on all suitable bottoms. As his investigations hi 1931 

 showed, it ranges on the border of the Kara Sea along the Nova Zembla channel as 

 far south as lat. 71 N. 



Poliometra prolixa is preeminently an inhabitant of soft bottoms, on which it is 

 supported by its long cirri. These are relatively inflexible, very brittle, and poorly 

 adapted to clinging to stones or arborescent organisms. Half the bottom records 

 are mud or clay, and most of the rest are mud or clay mixed with sand, gravel, or 

 stones. There are a few records of hard bottom, but it is not certain that the animals 

 lived on the spot from which the bottom sample came. 



The largest specimens, with arms more than 100 mm. in length or with more than 

 45 cirrus segments, are from Discovery Bay, Danmark station 104, Jan Mayen, Thor 

 station 51, Ingolf stations 124, 59 and 143, and the Faroe Channel. 



These stations are in Grinnell Land, and off northeastern Greenland, Jan Mayen, 

 northeastern Iceland, and the Faroes, in 46 to 905 meters, with bottom temperatures 

 between -0.1 C. and 0.6 C. 



