(fig. 5 H–J)
Sertularella tenella — Cornelius, 1979: 292, fig. 24. Sertularella geniculata — Leloup, 1974: 28, fig. 23.
Material examined. Stn. YBU — 26.iv. 2011, S 15 (20 m): several sterile stems, 4–11 mm high, on worm tube.
Description. Stems unbranched, more or less geniculate, divided into 785–2500 µm long internodes, 130–180 µm wide at nodes. Hydrothecae long, tubular, 300–360 µm wide, adnate for 2 / 5 th of their length, perisarc wrinkled more distinctly on adcauline side. Abcauline wall 560–640 µm long, free adcauline wall 385–425 µm, adnate part 285–385 µm. Aperture slightly expanded, 260–300 µm wide. Four marginal, pointed cusps separated by moderately-deep, rounded embayments; operculum composed of four triangular plates with concentric striations. Gonothecae missing.
Remarks. The present material is undoubtedly conspecific with that assigned by Leloup (1974) to S. geniculata Hincks, 1874.
Distribution in Chile. Tocopilla (Leloup 1974), Reloncaví Sound area (present study).
World records. Nearly cosmopolitan (Schuchert 2001).