6 NEW SPECIES OF GRANIA (OLIGOCHAETA, ENCHYTRAEIDAE) FROM THE ROSS-SEA, ANTARCTICA

Six new species of marine Enchytraeidae, Grania hirsuticauda sp.n., G. acanthochaeta sp.n., G. carchinii sp.n., G. angustinasus sp.n., G. an tarctica sp.n. and G. algida sp.n., are described from benthic materia l collected in McMurdo Sound during 1959-61 and Terra Nova Bay in 1988 . They represent the first records of this family from below the Antar ctic circle and, together with tubificids, the first oligochaetes from the Ross Sea. G. hirsuticauda, apparently the most widespread species in McMurdo Sound, is distinguished by having setae abruptly larger in the posterior third of the body and almost nodulate; a T-shaped prost omial bifurcation of the dorsal vessel, short sperm funnels and sperm sac, and thick-walled spermathecae. G. acanthochaeta possesses a uniqu e, thorn-like, setal morphology and diverticulate spermathecal ampulla e. G. carchinii, the only new species lacking lateral setae, is also d istinguished by a remarkably high development of the chloragogen tissu e and the possession of nephridia at 6/7. G. angustinasus, the most ab undant species in the sampling area in Terra Nova Bay, and G. antarcti ca, have the same setal distribution, size and (curved) shape, but sho w different forms of penial bulbs (more complex in G. angustinasus) an d spermathecal structures (the ampullae being larger and the external pores more posterior in G. antarctica). G. algida is distinguished by its L-shaped setae and carrot-shaped, diverticulate, spermathecal ampu llae. All the new species lack cuticular penial stylets as well as spe rmathecal ectal glands. All species but G. carchinii are peculiar in p ossessing, in front of the brain, a middorsal vesicular body of specif ic shape and size containing a few refractile inclusions; a sensory (p ossibly a statocyst-like) function is suggested for this 'head organ', which has not been previously reported in the Oligochaeta.