[1] This worm has bioluminescent properties; its body fluids and the sticky slime it exudes when stimulated emit a bluish glow.

The two ends of the worm are brown, the clitellum reddish-brown and the rest of the body is a rather dull salmon pink.

The light is produced in the coelomic fluid and is emitted when a luciferin called N-isovaleryl-3-amino-propanal is acted on by a peroxidase-like luciferase.

[2] This is a copper-containing protein which reacts with the hydrogen peroxide that is produced by another enzyme in the presence of oxygen.

Light is emitted by certain large cells in this fluid when they rupture, and the worm is visible as a dark silhouette against the luminous slime.