Luminescent Responses in Chætopterus and the Effects of Eserine

Abstract

ANIMAL luminescence comprises two broad categories, namely, those in which light is produced by the animal, and those in which it is due to symbiotic bacteria; but in either event it may be under the control of the animal. The emission of light would then be a significant indication of the progress of underlying physiological events, and by quantitative recording should provide information about the physiology of luminescent effectors. Considerations of this kind have prompted a study of the physiology of light production in the polychæte Chœtopterus variopedatus. This is a well-known luminescent worm about 10 cm. long that discharges a luminescent secretion from definite circumscribed glands in certain regions of the body¹. The glandular cells responsible are elongated eosinophilic elements packed with a paraplasmic mass of secretory granules, and when animals are excited and killed simultaneously by dropping into a fixative, the photogenic cells are caught in the act of secreting, and have the appearance of squeezing forth their contents².