Salmacina tribranchiata (Moore, 1923) and Spirobranchus minutus Rioja, 1941b. Salmacina tribranchiata: A) Entire body, tube removed, B) radiolar crown and thorax, C) abdomen and pygidium, D) tubes. Spirobranchus minutus: E) radiolar crown and operculum, F) opercular peduncle and operculum. Scale bars: A–C) 0.2 mm, D) 2 mm, E) 1 mm, F) 0.5 mm.