- Key facts
Length up to 10 cm, width usually up to 5 mm although wider when contracted. Head not wider than body and with a pale characteristic groove median ridge running from nose to neck. Several (up to 30 or more on each side) more or less distinct eyes along the sides of the head. Body dorsally brownish yellow or pinkish, ventrally paler. Body rounded, tail thick and broad. Mouth with darker grains of pigment scattered around. Very contractile when irritated. Head can be withdrawn into the furrows, working as a collar.