(Alder & Hancock, 1843)
North Atlantic - northern British Isles, Norway, Nth American coast from Canada to Massachusetts, USA.
UPPER: April 1988 - Stromemore, Loch Carron, W. Scotland. Photo: Bernard Picton.
LOWER: at Sea Point, Maine, USA, April 1976, Photo: Alan Kuzirian.
Grows to about 40mm long. The body is translucent white and the tips of the oral tentacles, rhinophores and tail are opaque white. The ceratal digestive gland is bright red and the tips of the cerata are capped with opaque white, instead of the subapical rings found in other northern Atlantic species.
Normally feeds on the hydroid Eudendrium arbuscula in the British Isles but other Eudendrium species, and sometimes Tubularia may be eaten. Thompson & Brown's report (1984) that it prefers Tubularia in European populations is apparently an error. Their statement that Kuzirian confirmed this dietary choice in North American populations is also incorrect, Kuzirian (1979) specifically stating that in prey choice experiments F. pellucida "chose Eudendrium dispar over Tubularia sp". The spawn consists of a thread which is laid in a wavy spiral coiled amongst the food and on nearby rocks.
The long cerata, of fairly even size, the red ceratal digestive gland and the white-capped cerata would appear to be good characters for this species.
• Kuzirian, A.M. (1979) Taxonomy and biology of four New England coryphellid nudibranchs. Journal of Molluscan Studies, 45: 239-261.
• Thompson, T.E. & Brown, G.H. (1984) Biology of Opisthobranch Molluscs, Vol 2. Ray Society: London.
Rudman, W.B., 2001 (July 16) Flabellina pellucida (Alder & Hancock, 1843). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/flabpell