FIGURE 2. External view and histology of Stephanauge prima sp. nov. A) On the left, top view of the body of holotype showing the arrangement of mesogleal tubercles. On the right, paratype grasping Diacria sp. shell (arrows). B) Transversal view of the actinopharynx and the two siphonoglyphs (asterisks) with mesenteries. Gametogenic tissue occurs in almost all mesenteries. C) Paratype upper half lateral view, showing the rows of tubercles and one cinclis (arrows). D) Cross section of the column at the actinopharynx level, showing cycles of mesenteries (roman numbers). E) Longitudinal section of the uppermost part of the column showing the processes in the mesogleal sphincter (arrow). F) Cross section of one tentacle, showing a larger side of mesoglea and the musculature. G) Cross section of a pair of mesenteries in the third cycle and the diffuse retractor muscle (arrow). H) Cross section of the upper column showing tentacles. Colored lines show each cycle (first cycle, blue; second, yellow; third, green; fourth, red). I) Cross section of the third and fourth mesenterial cycles. Abbreviations: ci, cinclis; lm, longitudinal muscle; me, mesoglea; ms, mesogleal sphincter; re, retractor muscle. Scale bars: A, H: 100 mm; B: 5 mm; C: 5 mm; D: 400 μm; E, F, G, I: 200 μm.