Specimen from Belfast Lough , Co Antrim, Northern Ireland. The body of this animal is translucent white. There are up to seven orange tipped processes on each side of the gills. A pair of longer processes project forwards from the base of each rhinophore.
White ovotestis is visible through the transparent epidermis.
The oral tentacles are short and tipped with orange. Orange pigment is also found on the tips of the rhinophores and on the tip of the tail. Occasional individuals can be found in which the orange pigment is replaced with white. Adult specimens may reach a length of 33mm. The prey is reported to consist of compound ascidians such as Botrylloides leachi , Botryllus schlosseri and Diplosoma listerianum , but it is possible that this species actually feeds on minute kamptozoans such as Pedicellina cernua which are epizooic on bryozoa and tunicates.