PHOSPHORESCENCE 



295 



itself round with its tentacles. Moreover, when the tentacles 

 were cut off the fish did not reject the body of the worm. The 

 tentacles are thus coloured in such a way that fish recognise 

 them, and associate with the colour some distasteful property. 



Phosphorescence. Many worms of very different habits 

 have the power of emitting a light from some parts of the body, 

 and they are then said to be "phosphorescent." 1 Probably 

 Chaetopterus is most eminently photogenic ; the base of the great 

 " wings," the " fans," and other parts emit, on stimulation, an azure 



Fia. 157. Chaetopterus variopedatus Ren. x \. On the left the entire animal, with 

 the three regions A, B, C. c, Peristomial cinus ; d, " sucker " ; e, the great 

 "wings";/, "fan" ; m, mouth. On the right the animal is represented in the 

 dark, under stimulation, so as to exhibit the phosphorescent portions of the body. 

 (From Panceri.) 



blue to greenish light, so bright that one may read one's watch 

 by it. Several species of Polynoe exhibit a similar phenomenon, 

 each elytron, with the exception of the area of attachment, being 

 brilliantly illuminated. In these species the phosphorescent 

 elytra are frequently thrown off by the animal, so that possibly 

 they deceive enemies. Polycirriis aurantiacus produces a beautiful 

 violet phosphorescence ; usually its many tentacles alone show 

 the light, but under strong stimulation the entire body takes 



1 Panceri, Atti Acad. Sci. Napoli, vii. 1875. 



