some Marine Invertebrata. 183 



surges of melted lead or silver, strewn with an infinite number 

 of bright scintillations, either brilliant white, or of a greenish 

 tinge. The spectacle is then most beautiful, and after having 

 witnessed it on a small scale, I understood the impression left 

 on the minds of travellers who have seen it under the tropics, in 

 all its magnificence. The following are the facts which I have 

 myself witnessed. 



The waves, in breaking on the nearly horizontal beach of the 

 cove, although so little elevated, covered quite an extent, and the 

 whole space presented a uniform and glowing tint, from which 

 started out innumerable scintillations yet more briUiant, and of 

 a bluish or greenish hue. 



As the water became absorbed by the sand, a line more 

 strongly luminous indicated its limit. This effect was especially 

 marked in the little ca\'itie3 which the shore presented, where 

 the line fomied concentric curves which diminished as these little 

 basins were exhausted. On passing a long stick rapidly in the 

 water, it presented in its whole length the appearance of a blade 

 of silver. 



The water taken up at random and poured out from a little 

 height had exactly the appearance of melted silver, and it was the 

 same in the slightest spray. It left upon the hands or clothes 

 bright spots that were quite persistent. At one time, when, on a 

 short excursion with M. Bouchard, a dog ran barking at us, we 

 threw at him the contents of a small cup, and he fled in terror 

 from what he seemed to take for fire, and troubled us no longer 

 save at a distance. If we plunged our hands into the sea, when 

 drawn out they were luminous all over, but after a few seconds 

 they were marked only here and there with bright spots, whose 

 brilliancy remained constant and without scintillations. 



The bank recently left by the tide did not however show any 

 trace of phosphorescence ; yet at the least shock it became lumi- 

 nous, and seemed literally to glow under the steps of the observer. 

 In some circumstances, wherever the foot rested on the sand or 

 gravel, it seemed like burning coals beneath the tread ; and this 

 appearance was equally perfect, with more or less briUiancy, even 

 to a distance of some inches. 



The Talitri, so numerous on our sandy shores, and whose 

 habits have gained for them from the fishers the name of sand- 

 flea, become luminous by contact with the phosphorescent water, 

 — a fact to be noted ; for at first one might be led to imagine 

 that they were the cause of the light. Nothing can be more 

 curious than to see these sand-fleas leaping by hundreds, and 

 appearing like the scattering of tiny sparks. 



2. The Animals that produce the phosphorescence in the two pre- 

 ceding cases. — a. At Chausey, Brehat, St. Malo, and Saint Vaast, 



