The external morphology of sabellids polychaetes gathered from green abalone (H. discus hannai) and 2 species of Chilean native gastropods (Fissurella sp. and Concholepas concholepas) was studied. According to the taxonomic keys of Fauchald (1977) and Rozbaczylo (1980), all of these polychaetes belong to the family Sabellidae; subfamily Fabriciinae, and genus Oriopsis (according to Day 1967 and Fitzhugh 1989). This work constitutes the first report of the presence of sabellids of the genus Oriopsis forming tubes in the shell of the green abalone Haliotis discus hannai. The worms analyzed correspond to small sized sabellids (1–2 mm long). The body is fusiform, not sacciform like T. heterouncinata. The gill crown is constituted of three pairs of radiolae, unlike T. heterouncinata counting with 2 pairs of radiolae. Another important difference with this sabellid previously reported habiting abalone shells is the shape of the abdominal uncini, in Oriopsis are rasp-shaped plates, without main fang, defining a clear difference with the abdominal uncini acicular with a single main tooth crowned with shorter series of teeth, characteristic of T. heterouncinata.