POLYCHAETE WORMS — PETTIBONE 541 



7 0kak area, Kiglapait Harbor, about 15 miles northwest of Port 

 .Manvers, 3-5 fms., Aug. 10, 1952; 5° C. (-1.8 to 8), 307oo. 

 Ilarniothoe imbricata (Linn6) (9) FlabelHgera affmis Sars (1) 



S Lake Melville, shoal area west of Gull Island, 17-20 fms., Aug. 24, 

 1952; 3.5° C. (-0.6 to 4.0), 257oo. 



Ilarmothoe extenuata (Grube) (5) Nereis zonula Malmgren (5) 



9 Lake Melville, The Backway, about 8 miles from east end, 

 54°06.3' N., 58°01.1' W., 16-20 fms., Aug. 25, 1952; 2° C. (-0.6 



to 2.0), 257oo. 



Melaenis lov&tii Malmgren (1) Branchiomma infarcta (Kroyer) 



(1) 



DiSTKIBUTION OF LABRADOR PoLYCHAETES 



^he systematic, ecological, hydrographic, and geographic distri- 

 lions of the Labrador polychaetes are summarized in table 1. 

 '3 collections include 1,187 specimens representing 68 species and 

 ^families of Polychaeta. The Polynoidae are the most abundant 

 Ito number of species (11) as well as number of specimens (22 

 icent of the total number). The Terebellidae, Sabellidae, and 

 ^ipharetidae each have six species. 



phe Labrador polychaete stations may be subdivided, on the 

 iis of the hydrographic data of temperature, depth, and salinity, 

 ) three main categories (see table 2 for summary of hydrographic 

 .a and station numbers) : 



Permanent High Arctic: Marine environment where the waters are con- 

 tinuous with those of the Arctic Ocean and circumpolar areas (Labrador 

 current water of Arctic origin). The water temperatures are below 0° C. 

 (mostly around —1.8° C.) the year round, the depths are generally 30 to 

 50 fathoms, i. e., below the upper layers where summer warming takes 

 place, and the salinity is about 32 °/oo. 



. High Arctic with Summer Warming: Marine environment where the Arctic 

 waters are in the shallow coastal areas and would be efifected by the 

 warming of the surface layers. The range of temperatures throughout 

 the year is —1.8 to 12° C, the depths mostly 4 to 40 fathoms, and the 

 salinity mostly between 30 and 32 °/oo. 



. Special Conditions in Greater Lake Melville Estuary: Lake Melville is 

 separated from Hamilton Inlet and the Atlantic Ocean by both a con- 

 striction and a sill (Nutt, 1953), resulting in a highly complicated exchange 

 mechanism. The stations within Lake Melville may be subdivided into 

 two categories: 



(a) Permanent High Arctic but not quite as cold. It includes the deeper 



areas of 30 to 100 fathoms, with bottom temperatures mostly 

 between —0.6 to 0.0° C., and sahnities of about 28 °/oo. 



(b) Mostly above 0° C. with greater or lesser summer warming. It in- 



cludes the shallower areas of mostly 15 to 30 fathoms, temperatures 

 of mostly to 2° C., and salinities of mostly 21 to 25 °/oo. 



