Plate P7. Scale bar = 10 µm. 1, 2. Triquetrorhabdulus carinatus (Sample 189-1168A-45X-3, 61 cm); (1) differential-interference contrast light (DIC); (2) polarized light (XP). 3-6. Triquetrorhabdulus challengeri; (3, 4) Sample 189-1168A-46X-2, 60 cm; (3) DIC; (4) XP; (5, 6) Sample 189-1168A-45X-3, 78 cm; (5) DIC; (6) XP. 7-10. Triquetrorhabdulus rugosus; (7-9) Sample 189-1172A-14H-3, 15 cm; (7) phase-contrast light (Ph); (8) DIC; (9) XP; (10) Sample 189-1172A-12H-6, 15 cm (Ph). 11, 12. Triquetrorhabdulus farnsworthii (Sample 189-1168A-24X-7, 15 cm); (11) Ph; (12) XP.