On the Phosphorescence of some Marine Invertehrata. 15 



cuius is seen adherent to the opposite side, and the axis of the 

 style is seen inclining to the ventral tuberosity. 

 Fie, 4. The same more magnified, shovring the cellular somewhat circuitous 

 •'' canal which extends from a, the ventral tuberosity, to the cavity of 



the ovarv ; the external and internal openings bemg closed only by 

 a thin layer of cellular tissue : the axis of the short style, together 

 with its tennination in the cavity of the carpel external to the 

 funiculus, and also the fibres of the funiculus, are here distinctly 



Fid 5 An^ovkry of Ceratophyllum demersum in longitudinal section. 

 m 6. A carpel of Hydropeltis purpurea in longitudinal section : a, tne 

 ^ ventral side which is turned towai-ds the axis of the polycarpous 



Fia 7 A°cSl of Cabomba aquatica, the dorsum having been removed. 

 Two ovules are seen attached to the lateral fibres, which are con- 

 tinued upwards and meeting at the ventral suture become con- 

 tinuous; at this part the third ovule is seen attached. 



Fig. 8. An ovary of Arum maculatum in longitudinal section : a, the ante- 



Fia 9 An°ovarv "of Sparganium ramosum in which the dorsal portion of 

 ^' ■ the stigma had become fissured; when dicarpous, which fre- 

 quently happens, the stigmatic surfaces of the two carpels are 

 turned towards each other. 



Fig. 10. Cryptocoryne ciliata : a, the fissured stigma. (Oriffltn.; 



Yl.— On the Phosphorescence of some Marine Invertehrata. 

 By M. A. De Quateefages*. 



I. Historical review of the Subject. 



1 Causes of phosphorescence.— It is well known that the 

 waters of the sea, in some latitudes and under certain cu-cum- 

 stances, are phosphorescent, producing a light more or less bril- 

 liant This remarkable phsenomenon has always attracted the 

 attention of travellers, and various have been the explanations 

 they have offered. Without going here into useless detail, we 

 will first mention those hypotheses which are now completely set 

 aside, before dwelling on better-founded opinions. 



Ancient navigators seem to have indicated a resemblance be- 

 tween the hght produced on the surface of the water and that 

 which is due to atmospheric phsenomena, by designating the 

 former " meteors of the sea." Something of this idea is evident 

 even in the vrritings of learned men, who endeavoured to explain 

 this phosphorescence solely by physical or chemical causes. Ihus 

 Nollet could see in it only a simple modification of electrical 

 phjenomena. Bajon, in his memoirs on the History ot Cayenne, 

 regards this Hght as due to the electricity of the waves, deve- 



* From the Annales des Sciences Naturelles, vol. liv. 3rd series, as in- 

 serted in Silliman's American Journal of Science for Mai-ch, Ibbd. 



