Description: This is a worm-like mollusc in the class Solenogastres. It is normally coiled around the main stem of the hydroid Lytocarpia myriophyllum.

Habitat: Exclusively found on the hydroid Lytocarpia myriophyllum which itself is confined to deeper water, below 25 m in sheltered but tide swept sites.

Distribution: A few records in Britain and Ireland from the Irish Sea and North Channel up to NW Scotland.

Key Identification Features:

• Worm-like body with groove on underside and no segmentation.

Distribution Map from NBN: Rhopalomenia aglaopheniae at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Rhopalomenia aglaopheniae at iNaturalist World Species Observations database.

WoRMS: Rhopalomenia aglaopheniae at World Register of Marine Species.