text: Mechanical stimulation to spines on the arm can cause Amphiura filiformis to bioluminesce in the blue range. The species has been found to possess a luciferase compound. The luciferase has been isolated to clusters of photocytes that exist at the tip off the arms and around the spines. What are believed to be photocytes based on evidence have been found around the spine nerve plexus, mucus cells, and what are believed to be pigment cells. It has been found that luminescence is controlled by the animal's nervous system. Acetylcholine is able to stimulate the cells through nicotinic receptors.