(McIntosh, 1873-74)
Description:
Nemertopsis flavida reaches a length of 40 mm but is only about 0.5 mm wide. The filiform body is rather flattened and anteriorly and posteriorly tapered. The bluntly rounded head bears two pairs of rather small black eyes, the anterior pair usually being the largest (N. flavida-detail). The colour is a uniform white, yellowish, pink, pale peach or reddish-brown, with pale lateral margins and a translucent snout. The alimentary tract and rhynchocoel are sometimes visible through the body wall and the gut contents may affect the colour in the intestinal regions. The blood system may be indistinguishable in life or be visible because of a red pigmentation; individuals with the latter condition have often been recorded as Nemertopsis tenuis . Future studies must determine whether Nemertopsis tenuis should be recognized as a separate species. The cephalic glands posteriorly extend behind the cerebral ganglia. Sexually mature individuals have been found in May, though in Danish waters specimens with ripe gonads are present during October and November.
Habitat:
Nemertopsis flavida is found both intertidally and sublittorally. It occurs in rock pools, beneath stones and boulders, in laminarian holdfasts, among algal fronds, in Zostera beds or in a range of sediments including shelly gravel, mud and sand. Sublittorally the species has been dredged from a depth of more than 300 m but is generally recovered from much shallower locations.
Distribution:
The geographic range extends from Denmark to the Mediterranean, although it is also recorded (as Nemertopsis tenuis ) from South Africa.