PLANKTONIC LARVAE OF SPIONID AND CHAETOPTERID POLYCHAETES FROM OFF THE WEST-COAST OF THE ANTARCTIC PENINSULA

Thirty-five plankton samples were taken during the austral spring, bet ween mid-October and early November, in the region west of the Antarct ic Peninsula, including the area southwest of Brabant Island, (ca. 65. 5 degrees S, 63.5 degrees W), northwest of the South Shetland Islands, off Elephant Island (ca. 61 degrees S, 56 degrees W), and in the nort hwest portion of Bransfield Strait. Somewhat more than half the sample s (51%) contain planktonic polychaete larvae, specifically the nectoch aetes of the Spionid, Scolelepis eltaninae Blake 1983 or the mesotroch a of the chaetopterid Phyllochaetopterus monroi Hartman 1967. Both spe cies are endemic to Antarctic waters, apparently a consequence of the circumpolar current which acts as a barrier to northward larval disper sal.