Favorinus blianus

Lemche & Thompson, 1974

The extended length can reach 30 mm, pale straw-yellow in colour but frequently exhibiting black pigment on the rear face of each rhinophore; this blackening is absent in the juveniles. Opaque white pigment streaks the dorsal faces of the oral tentacles, and of the propodial tentacles and the metapodium, as well as covering the distal tips of the cerata. The digestive gland lobes within the cerata are pale yellow-brown in colour. The numerous cerata are arranged in horse-shoe clusters, but this arrangement may be hard to discern; the cerata tend to sweep inwards over the dorsum. Each ceras is somewhat flattened in section. The two rhinophores are placed close together and are shorter and stouter than the finger-like oral tentacles. The rhinophores widen a little from the base up to the three ring-shaped swellings characteristic of F. blianus. Stout, recurved propodial tentacles are present.

This species is known to consume cnidarians such as Tubularia; the spawn of other nudibranchs is also eaten and fully formed embryos of the prey may be discerned within the digestive gland lobes.

It has been recorded from Pembrokeshire, Cornwall, N. Devon, Lundy and other west-facing coasts of the British Isles, to 35 m, as well as from Norway and Denmark to the Galician coast of Spain (Distr. F. blianus).