Body medium sized, elongated, wider just before the branchial plume, which is located in the middle of the notum. Scattered tubercles of different sizes are found throughout the body surface. The frontal veil of the head bears four to six elongate processes, two or three on each side. There is also a group of extrabranchial finger-like appendages to the side of the gills (three per side). Branchial plume composed of 9-12 tripinnate gills. Rhinophores perfoliate, without sheaths, and oral tentacles short and simple.
general body color translucent whitish-grey densely peppered with black greyish dots, giving the animal an overall grey-black appearance. Papillae translucent white with a yellow-gold ring towards the centre. Tip of the tail also gold. White pigmentation forms irregular white lines on the edges of the notum and along the mid dorsal line of the foot.
common size :
10-20 mm, max. 40 mm.
It is readily distinguishable from the others Mediterranean species of Polycera. P. quadrilineata and P. elegans show a conspicuous and bright pattern of orange pigmentation. P. dubia has a cryptic coloration, as in P. hedgpethi, but its velar appendages and extrabranchial processes are clearly shorter.
BIOLOGY / ECOLOGY
Temperate-tropical species that is frequent in fouling communities on ship hulls.
on the branching bryozoans Bugula neritina 0-1 m deep in lagoonal environments, together with typical fouling organisms, such as the ascidian Ciona intestinalis.