McIntosh, 1873-74
Description:
Up to 30-35 mm long and 0.7-1.0 mm wide. A strikingly and characteristically coloured species: the background colour is orange, pinkish-brown or yellowish, marked with a transverse brown band, which encircles the body at the rear of the head (Tetrastemma robertianae). This band may be ventrally incomplete. From the rear of the band a pair of dorsolateral brown stripes run toward and may meet at the tail. A mid-dorsal longitudinal stripe of white pigment extends posteriorly between the brown stripes, and white pigment patches also occur on the head between the two pairs of eyes; sometimes this white cephalic pigment is developed into a broad transverse band. The eyes are black, the anterior pair being significantly larger than the posterior one. The ventral surface is a pale pinkish brown. The body is rather flattened and bluntly rounded at the posterior tip. The head is rhomboidal in shape, wider than the succeeding body regions and anteriorly blunt. Cephalic glands are well developed, posteriorly extending to cerebral ganglia. The dorsal cerebral ganglionic lobes are small. Cerebral sensory organs are moderately large.
Habitat:
A sublittoral species. Found at depths to 70 m or more on mud, shelly gravel and stones, or in shallow waters among laminarian holdfasts.
Distribution:
Extends from Scandinavia to the British Isles.