574 PROCEEDINGS OF THE NATIONAL MUSEUM vol. los 



Description: Paleae very smajl, rudimentary (smaller than 

 notosetae). Branchiae 8, in two groups. Oral tentacles pinnate. 

 Abdominal segments 12, with neuropodial cutI. Two anal cirri. 

 Tube muddy, gray, compact, smooth. 



New records: Labrador: Seven Islands Bay, Hebron Fjord, 

 30-125 fms., on bottoms of mud, stones, and mud with rock; 12 

 specimens. Stations 11, 12, 31, 41. 



Distribution: Widely distributed in the Arctic: Siberian Arctic, 

 Greenland, Spitsbergen, Barents Sea, Novaya Zemlya, Kara Sea. 

 Also Iceland, Norway to England; Labrador. In 5 to 153 fathoms. 



Family Teres ellidae 

 Genus Pista Malmgren, 1865 



Both species have a single pair of branchiae, with large main stem 

 and branched dichotymously. Cephalic ridge with numerous eye- 

 spots. Two pairs large lateral lobes on segments 1 and 3 (anterior 

 and posterior to branchial segment). 



Key to the species of Pista from Labrador 



1. Thoracic setigers 15. Tube of muddy sand in form of 2V2 to 3 windings in 



horizontal plane, flattened oval in cross section P. flexuosa 



Thoracic setigers 16. Tube cylindrical, membranous, with small pebbles of 

 varying sizes, debris, bryozoans, parts of other worm tubes, algae, etc. 



P. maculata 



Pista flexuosa (Grubf, 1860) 



Terebella flexuosa Grube, 1860, p. 102, pi. 5, fig. 2. 



Axione flexuosa Malmgren, 1865, p. 384, p. 24, fig. 68. — Moore, 1909b, p. 141. 



Pista flexuosa Hessle, 1917, p. 162. — Annenkova, 1937, p. 191; 1938, p. 205.— 



Treadwell, 1937, p. 162.— Zatsepin, 1948, p. 155, pi. 38, fig. 10.— Wesenberg- 



Lund, 1950a, p. 52; 1950b, p. 120; 1953, p. 98. 

 Scione flexuosa Augener, 1928, p. 790. 



Some spechnens shared their curved tubes with the polynoid com- 

 mensals, Arcteohia anticostiensis. 



New records: Labrador: Seven Islands Bay, Llebron Fjord, 

 Nain, Hamilton Inlet, west end Lake Melville, 10-125 fms., on 

 bottoms of mud and mud with stones and rock; 40 specimens, Stations 

 10-12, 33, 38, 43, 50, 52, 57. 



Distribution: Widely distributed in the Arctic: Siberian and 

 Canadian Arctic, Greenland, Spitsbergen, Novaya Zemlya, White 

 Sea, Kara Sea. Also Labrador to Newfoundland; Okhotsk Sea to 

 north Japan Sea. In 4 to 211 fathoms. 



Pista maculata (Dalyell, 1033) 



Pista maculata Wesenberg-Lund, 1953, p. 97. — Pettibone, 1954, p. 323, fig. 36, k, 1. 



