Notaulax yamasui sp. n.: A holotype, dorsal view B ventral view of thorax C latero-dorsal view of left side of thorax D dorsal view of first chaetiger and radiolar base E distal side view of radiole F middle region of radiole showing a row of simple radiolar eyes G lateral close up view of tip of radiole, with pigmented sub-distal swelling H basal part of radiole showing paired longitudinal flanges (f) I schematic ventral view of interior of crown showing dorsal lip (dl), ventral lip (vl), ventral flange of radiolar base margin (vf) J posterior abdomen and pygidium, showing eye-spots K schematic arrangement of collar chaetae, right side L schematic arrangement of thoracic chaetae from second chaetiger, black spots representing superior chaetae, white circles representing inferior chaetae M anterior abdominal segment, left side view N schematic arrangement of neuropodial abdominal chaetae O cross-section of radiole, middle region P base of radioles and inter-radiolar membrane. Abbreviations: df, dorsal basal flange; dl, dorsal lip; f, longitudinal flange; j, junction of dorsal basal flange; vf, ventral flange; vl, ventral lip; w, inter-radiolar membrane. Scale bars 1 mm (A, B, C), 0.5 mm (D, J), 0.25 mm (E, F, H, K, P), 0.1 mm (G, I, L, M, N, O).