Special Topics

Phosphorescence in Certain Annelida

The property of phosphorescence occurs in the families Polynoidae, Syllidae, Chaetopteridae, and in Polycirrus and Lumbricus. In the first-mentioned, light greenish and somewhat steady scintillations are given off at the attachment of each scale, and the separate organ gleams with pulsations of light at the ruptured surface. It was probably the latter appearance which caused M. de Quatrefages to taste that it was emitted in muscular contraction. The synchronous emissions of light by the Italian fire-flies is interesting in this respect. In the Syllidae the light comes from the under surface of each foot; on Choetopterus the most vivid luminosity is on the dorsum of the tenth segment; and Polycirrus is so phosphorescent, that the slightest tremor in the water causes vivid pale bluish fire to gleam along every tentacle. The exact physiology of the luminosity is still open to investigation, though P. Panceri of Naples connects it with certain fatty granules. The luminous emissions have no connection with light or darkness, with the capture of prey, or the alluring of their enemies, nor with the illumination of the depths of the sea.





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