WoRMS note details

Wesenberg-Lund (1941) was the first (fide Uschakov, 1982) to report that Harmothoe bathydomus [now Eunoe] was a commensal of Holothuroidea (on Bathyplotes natans). There is, however, uncertainty whether Wesenberg-Lund's specimen was the same species as Ditlevsen's (Uschakov, 1982; Shields, Glover & Wiklund, 2013). No subsequent authors who recorded the species have examined the holotype, which was an anterior fragment of 28 segments. The characteristic mammiliform tubercles on elytra as figured by Ditlevsen were not seen in Wesenberg-Lund's specimen, and her specimen uniquely had faint eyes. Shields, Glover & Wiklund (2013) report the association was with the holothurian Deima validum validum
Wesenberg-Lund, Elise 1942. Notes on Polychaeta I. 1. Harmothoe bathydomus Hj. Ditlevsen refound. 2. On the sabellid genus Fabricia. 3. Three polychaetes from Ringk bing Fjord, unrecorded from Denmark. 4. Merciella enigmatica Fauvel, a serpulid new to Denmark. Videnskabelige Meddelelser fra Dansk naturhistorisk Forening i Köbenhavn 105: 31-47.