TUBIFICIDAE (OLIGOCHAETA) FROM THE ROSS SEA (ANTARCTICA), WITH DESCRIPTIONS OF ONE NEW GENUS AND 2 NEW SPECIES

Three species, Topodrilus gelidus sp. nov. (subfamily Rhyacodrilinae), Rossidrilus terraenovae gen. et sp. nov. (Limnodriloidinae), and a se cond unnamed species of Limnodriloidinae, are reported from marine sed iments in Terra Nova Bay, Ross Sea. Torodrilus gelidus is distinguishe d from T. lowryi Cook, 1970 by its setal pattern (with few exceptions, both anterior and posterior setae are single-pointed in sexually matu re specimens of T. gelidus) and the morphology of its male protuberanc es (the latter folded over a midventral bursa in segment XI). Rossidri lus terraenovae is characterized by large diverticula attached to the oesophagus in the posterior part of segment IX, unpaired male and sper mathecal pores, heavily muscular and entally ciliated atrial ampullae, elongate prostatic pads, and a deep, unpaired and muscular, copulator y sac. It is the first species of its subfamily to be described from A ntarctic waters.