THE MARINE ENCHYTRAEIDAE (ANNELIDA, OLIGOCHAETA) OF THE EASTERN COAST OF NORTH AMERICA WITH NOTES ON THEIR GEOGRAPHICAL DISTRIBUTION AND HABITAT.

1. Marine Enchytraeidae from the Eastern coast of North America were examined. Six genera and thirteen species are reported, four genera and eleven species are new to the American continent. 2. One new genus and two new species are described on material received from the Biotic Census of the Systematics-Ecology Program at the Marine Biological Laboratory: Hemigrania nov. gen., Lumbricillus codensis nov. sp. and Marionina welchi nov. sp. Three species are included in the new genus: Hemigrania postclitellochaeta (Knöllner, 1934), Hemigrania monochaeta (Michaelsen, 1888), Hemigrania principissae (Michaelsen, 1907); three species are related to Marionina welchi nov. sp.: Marionina subtilis (Ude, 1896), Marionina paucispina (Eisen, 1904) and Marionina normani (Michaelsen, 1907). 3. Marine Enchytraeidae are found in both littoral and sublittoral biotopes. Four categories of habitats are briefly described, (a) salt marshes, (b) the dirftline of seaweed deposit, (c) intertidal sand beaches, with well-sorted sediment and very small amounts of detritus, (d) the subtidal biotopes with very well-sorted sandy sediments. 4. The marine Enchytraeid fauna is composed of eurythermic cold water species, very abundant on the north eastern coast of North America (the Woods Hole region, Massachusetts), and also present under the warmer latitudes of the Beaufort region, North Carolina.