2 NEW SPECIES OF THAUMASTODERMA (GASTROTRICHA, MACRODASYIDA) FROM THE WEST-COAST OF NORWAY

Two new species of Thaumastoderma (Gastrotricha, Macrodasyida) are described from the Bergen area, western Norway. Th. truncatum sp. n. inhabits shell gravel of exposed places; Th. bifurcatum sp. n. is mostly found in finer sediments of less exposed places, and is reported also from the Trondheim and Tromso areas. Both species have one pair of spatulate tentacles and lack eyespots. Th. truncatum can be distinguished from other members of the genus by these characters: six pairs of dorsal cirri, fourth pair being especially long; looped vas deferens. Th. bifurcatum is distinguished by long posterior dorsal cirri and a long adhesive tubule directly below, with the impression of a double 'furca'. A key to the species is included.