among certain Annelides and Ophiuridce. Ill 



that in the electric discharges of fishes, the shock, though very strong, is 

 accompanied with only a feeble and dull spark. The ingenious experi- 

 ments devised by M. Masson, have, it is true, demonstrated, that with a 

 very feeble source of electricity we may obtain very violent shocks, in 

 which notwithstanding, the sparks are scarcely visible. With the help 

 of his apparatus, he has produced the electrical phenomena of fishes in all 

 their minute circumstances, but, in the explanation which he has given 

 of these facts, he is always obliged to admit, that at the moment of the 

 shock, the electricity accumulated in the spinal nerves rapidly ; that it 

 consequently acts in considerable quantities, although the source whence 

 it emanates appears to give origin only to a very feeble current. In the 

 theory of M. Masson, or in that of others, the violent shock which is felt 

 in coming into contact with the torpedo and the gymnotus, is owing to 

 a great mass of electricity dispersing itself rapidly among our organs, 

 and the disproportion between the intensity of the luminous phenomena 

 observed, and that which we should have been led to expect, does not 

 the less exist. 



But in the annelides and the ophiuridas we have been able to recognise 

 only the production of light : it would be interesting to discover if there 

 be not at the same time traces of electricity. This investigation cannot 

 evidently be undertaken upon the species which we have observed, their 

 minuteness opposing all attempts of this kind. But it is well known that 

 M. Duges has discovered in the stones in the neighbourhood of the volcano 

 of Agde a large specimen of the genus Syllis which he has designated by 

 the specific appellation oi fidgurans, whose luminosity is without doubt of 

 the same nature as in its congeners. It is probable that this species is 

 not confined to the locality in which the Montpellier Professor has dis- 

 covered it ; and I shall take the liberty therefore of pointing out this ani- 

 mal to those naturalists and physiologists who are on the shores of the 

 Mediterranean as a most suitable subject for the experimental enquiry 

 to which I have alluded. It would be curious to discover in the modi- 

 fications, luminous or electrical, of the agent on which we have been 

 dwelling, a kind of balancing or fluctuation, whence it should result that 

 in the same animal, the one cannot, so to speak, predominate, except at 

 the expense of the other.* 



* I must here make one remark concerning the facts I have been detailing. 

 We cannot on all occasions procure animals whose phosphorescence is so strong 

 that it will be seen when we use magnifiers. Generally we only discover a 

 feeble glimmer when using a magnifying power of ten diameters. Naturalists 

 therefore who wish to repeat these observations must not be discouraged if they 

 meet with some disappointments before they succeed. — (From Annalea des Sciences 

 Naturelles, Mars 1843, p. 183.) 



