Peinaleopolynoe santacatalina specimens A SIO-BIC A8487, live dorsal view B Peinaleopolynoe santacatalina observed on the Rosebud Whalefall off the coast of San Diego, CA C SIO-BIC A8489, live dorsal view without elytra. Numbers next to the elytrophores indicate the pairs of elytra (ten total) D SIO-BIC A10927, live ventral view. Arrows indicate the four pairs of papillae on segments 12–15. Abbreviations: el, elytrophore; br, single large group of branchiae on elytrigerous segment; br1, branchiae small group 1 attached to dorsal tubercle on cirrigerous segment; br2, branchiae large group 2 attached near base of notopodium on cirrigerous segment. Scale bars: 5 mm (A, C, D); 10 mm (B).