Specimen from 8 m depth at Split, Croatia. Length 25 mm. © J. Prkić.
This specimen was molecularly sequenced by Carmona (2020), who found a difference of 8% from sequences of Scottish and Swedish F. bostomiensis.
Features below, based on / calculated from Bergh (1882), are of a single 40 mm, live specimen of F. vicina (lost holotype).
Body length/width 4.7. [Split specimen approximately 4.]
Cerata up to 22.5 % of body length. [Split 50%.]
Dorsum of tail, proximal half of oral tentacles and anterior face of cerata have bluish-silver iridescence. [Split; less intense than fig 26. Extent and intensity varies; absent from a few in Croatia .]
Cerata have a chalky-white tip. [Recent Croatian finds also have an opaque white line (1) or dots running down from the white tip .]
The lamellated rhinophores have a median row of discrete, elongated white spots between and behind them (2), almost to the pericardium.
Bright rosy red head, particularly intense on the front and under the neck. [Red absent from this Split specimen and several others from Croatia.]
Long oral tentacles (3) nearly twice as long as rhinophores, 25% of body length. [Split; almost as long as not-fully-extended body.]