OF all the groups of organisms which recent investigations have discovered in the deep oceans, probably none have become more widely divergent from their littoral relatives and more particularly adapted for a free-swimrning life far beneath the surface of the water than have the nernerteans. The object of this paper is to call attention to some of these special adaptations, but with particular reference to the material collected by the U. S. F. C. S. Albatrsoss in various parts of the Pacific Ocean. The results of a detailed study of this material have been published in monograph form during the past year (Coe, '26). Although the total number of described species of neMerteans is less than six hundred, they are very widely distributed, being found on the bottoms and along, the shores of all the oceans, less commonly in fresh water, and occasionally in moist earth and even in moist cavities on trees. They are most numerous along the sea-coasts of Europe and North America, but relatively few species extend along the bottom into the deep oceans whllich lie beyond the continental shelves. In the open oceans they are represented by a highly specialized group of the Hoplonemertea, constituting the tribe Pelagica, with peculiar adaptations for slowly swimming or floating idly in particular water layers which lie at considerable depths. It is with this bathypelagic group that this paper deals. Forty-seven species 'of these highly modified forms have been described. These have been grouped in nine families and twenty-five genera. The members of each