among certain Annelides and Ophiurida;. 105 



appears to us more than probable that the phosphorescence of de- 

 caying wood and fishes, &c., is due to a slow combustion. We are 

 also much disposed to attribute to the same cause the light given off 

 by some animals, particularly that disengaged by the Lampyres and 

 the ElateridsD. This explanation, however, becomes doubtful when we 

 apply it to the animal secretions of certain mollusca. We have, at all 

 events, heard M. Milne Edwards, in his lectures, cite a fact on this 

 point which is highly curious. Wishing to place some living Pholades 

 in alcohol, he observed a luminous matter exude from the bodies of 

 these mollusca, which, on account of its weight, sank in the liquid, 

 covering the bottom of the vessel, and there forming a deposit as shin- 

 ing as when it was in contact with the air. 



During the sojourns I have made upon the shores of the British 

 Clumnel, I have often had occasion to observe the phosphorescence of 

 the sea. So far as my observation has extended in deep water, how- 

 ever, the phenomenon is alwaj-s limited to sparks, bright but not nt;- 

 merous, which the dash of the oar or the prow of the vessel instan- 

 taneously produced, and which as rapidly disappeared. In other cir- 

 cumstances, again, I have noticed the fuci which grow upon the beach 

 resemble an entirely incandescent mass. To witness this spectacle, which 

 I observed particularly at Chausey in the summer of 1841, all that was 

 necessary was strongly to agitate some of the branches which had 

 recently been left bare by the receding tide, when my hand became im- 

 mediately as if set on lire. It was principally annelides which produced 

 this light ; and scarcely less so small ophyures. Besides, I am also 

 sure that some microscopic entomostraca also become momentarily 

 luminous ; and it is to these last, especially, that 1 attribute the very 

 brilliant scintillations I have witnessed on several parts of the coast. 

 At all events, in examining with my glass, with the greatest care, a cer- 

 tain quantity of water taken from these localities, and which gave out 

 sparks in my flask, I have found no other creatures but these last- 

 ramed animals. 



The observations which follow refer solely to the annelides and the 

 ophiuridae. The former consisted of some niinute species of nereidse, 

 especially of the genera Syllis and Polynce, some of which I regtird as 

 nev.-, but will not here describe. We as yet know too little of these 

 insignificant creatures which swarm on the margin of the ocean to 

 enable us to recognise, with an}- degree of certainty, whether they are 

 full-grown or otherwise, except when we find them bearing eggs ; and, 

 under the circumstances, I have thought it better to abstain from con- 

 jecture. At the same time, one of them, which most strikingly 

 exhibited the phenomena of phosphorescence, presented a zoological 

 character which is quite remarkable — namely, that the aciculi with 

 which its feet are armed, instead of being of a conical form as is usually 

 observed, terminate in a kind of pallet with cutting edges, divided into 

 two not very diotinct lobes, the one of which is more developed than 



