Description: The cerata in this species are normally filled with red-coloured digestive gland, but green individuals (var. smaragdina) are found on occasions. The body is translucent white, with patches of white pigment at the tips of the rhinophores, oral tentacles and tail and thin rings of white pigment at the tips of the cerata. The anus is beneath the gap between the second and third bunches of cerata. A small species, reaching 12mm to 15mm at maturity.

Habitat: Found mostly in semi-sheltered conditions where there is water movement from tidal streams. Feeds on Eudendrium spp., especially Eudendrium arbuscula and is usually abundant when found. The spawn is a white string wound untidily amongst the food. When laid on a flat surface it forms a grecian-key type pattern.

Distribution: Recent records are from western Scotland and north, east and south coasts of Ireland. Further positive records include Iceland and the Atlantic coast of America.

Similar Species: Easily confused with juveniles of other Coryphella species, but the presence of internal opaque white globules of mature ovotestis in animals of 10-12mm is a good identifying feature.

Key Identification Features:

• Anus position between second and third ceratal clusters.
• Small size at maturity.

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

iNaturalist: Coryphella gracilis at iNaturalist World Species Observations database.

WoRMS: Coryphella gracilis at World Register of Marine Species. Accepted name: Coryphella gracilis (Alder & Hancock, 1844). AphiaID: 139981.

Classification: Biota; Animalia; Mollusca; Gastropoda; Heterobranchia; Euthyneura; Ringipleura; Nudipleura; Nudibranchia; Cladobranchia; Fionoidea; Coryphellidae; Coryphella