52 NATURAL HISTORY SOCIETY OE DUBLIN. 



luminous would continue longer than a year, and then it would, when 

 plunged in warm water, give as much light as ever. Many of the 

 Annelids, both terrestrial and marine, but especially the latter, are phos- 

 phorescent. The genera of Nereis, Syllis, Polynoe, Choetopterus, and 

 Sabella, possess this property. Dr. Allman, many years ago, brought 

 before the Natural History Society of Dublin a notice of the fact, new 

 at the time, that a small Annelid possessed of luminous powers is 

 frequently found in turf. He observed in the month of September 

 that some of the turf bogs in the western parts of the county of Cork 

 exhibited by ni^ht, on the recent removal of their surface, a great 

 many minute luminous points, presenting almost the appearance of the 

 sea when its waters are agitated during the night. This appearance 

 was very transitory, lasting but for a few seconds after the exposure 

 of the subjacent peat, and requiring for its subsequent manifestation 

 a second removal of the surface. On bringing home some of the 

 luminous peat, and making a careful examination of it, he found 

 that this interesting phenomenon was caused by a small white setige- 

 rous Annelid, about half an inch in length. The power of emitting 

 the light appeared voluntary, and to require for its manifestation that 

 the animal should in some way be irritated. On holding one of them 

 over alcohol, an exceedingly brilliant phosphorescence would take 

 place, and last for a few seconds, excited, doubtless, by the irritation 

 of the alcoholic vapour. This phosphorescence consisted in a very 

 beautiful clear green light, and did not appear to be confined to any 

 particular spot, the entire animal appearing luminous. He found 

 upon inquiry that the phosphorescence of the bogs was well known to 

 the country people of the western part of the county of Cork, though 

 not referred by them to this cause. The cause of the phenomenon 

 was a small white Annelid about half an inch in length, and com- 

 posed of a number of setigerous rings, very distinct after the animal 

 has become contracted from immersion in spirits. Each ring bore a 

 fasciculus of very minute setse on either side, requiring, in order to 

 render them visible, a very high magnifying power. Duges has 

 described a luminous Annelid, which he called Lumbricus phosphoreus, 

 found by him in the tan of the hot-houses in the Botanic Garden of 

 Montpelier. And it is not improbable that the phosphorescence of the 

 turf- mould in Staffordshire, alluded to by Dr. Plot, may have been due 

 to an analogous cause. A common centipede, the Geophilus phosphorea, 

 is one of the phosphorescent Myriapoda. This centipede has been dis- 

 covered in considerable numbers on the Hill of Howth by Dr. Stokes, 

 who drew Dr. Allman' s attention to its presence there, and is very 

 generally distributed throughout the country. Fearing to be weari- 

 some, I shall not go through the luminous genera of Crustacea, and 

 shall conclude with a brief reference to the phosphorescent phenomena 

 exhibited by insects. In the Hemipterous order of this class (Insecta), 

 are the lantern and candle flies, whose luminosity has been very much 

 questioned, but it is now pretty generally believed t that they are 

 luminous, but not equally so in both sexes, and not continually so, but 

 occasionally or periodically. 



