Abstract
Specimens of A. locyi Erseus, 1980 (Oligochaeta, Tubificidae) from Coos Bay, Oregon, USA, are compared with the original California material, and A. oregonensis sp. nov. is described. A. locyi was found in the upper to middle intertidal in sands with .ltoreq. 8% silt. A. oregonensis occurs lower on the beach than A. locyi and in the upper intertidal only in sand with 8% silt. An interaction of tidal height and sediment type affects the distributions of both species.