70 On the Phosphorescence of Marine Fnvertebrata. 
coasts, did not seem to understand my inquiries relative to a more 
general or diffused phosphorescence. M. Beautemps-Beaupreé, 
mentions his observing phosphorescence of this kind during one 
of the numerous excursions in which he was engaged, while 
in some yell sheltered harbor, like the port of Paimpol. 
the sea itself rarely presents any remarkable phosphorescence 
in the localities of which I am about to speak, it is not so with 
the marine plants which are left by the tide. In some circum- 
stances, I have seen masses of the Fucus kindle up when seized 
a little rudely; but even then the light was in isolated points, 
which the eye easily distinguished from one another. In no case 
did the stalks or the leaves present the uniform tint of a metal at 
a white heat, and the water which ran out freely was never lumit- 
ous. Moreover, the part of the beach which the sea had just 
left dry, remained perfectly dark. At most, only a few sparks 
might be seen over a space of some extent. 
Water drawn from the sea in the circumstances of which I 
peak, and when the scintillations were most numerous and most 
brilliant, often became suddenly obscure, or presented only some 
diminished and perhaps destroyed towards the entrance, between 
the two dykes. It is very decided through the whole port pro- 
perly so called, in the basin, and especially in the little cove 
named the “ Parc aux huitres.” The last locality being very 
accessible, afforded opportunity for studying all the details of the 
phenomenon. 
However favorable the circumstances for observation, the water- 
when quiet was always perfectly dark ; but the least movement 
drew forth light. A grain of sand cast upon the dark surface 
produced a luminous spot, and the undulations of the water were 
so many bright circles. A stone as large as the fist, produc 
the same results in a more intense degree, and moreover each 
