84 
XATURE XOTES 
One of the most common is the night-shining nereis — Nereis 
noctiliica. The body of this little creature is a mere oblong speck, 
so minute as to elude examination by the naked eye. It inhabits 
every sea, and is one of the causes of the shining of the water 
in the night, which is sometimes so great as to make the water 
appear as if on fire. Myriads of these creatures are found on 
all kinds of seaweeds, but they often leave them and swim on the 
surface of the water. They are common at all seasons, but 
particularly in summer before stormy weather, when they are 
more agitated and more luminous than at other times. Their 
numbers and wonderful agility, added to their luminous property, 
must contribute not a little to that phosphorescence so often 
observed on the ocean ; for myriads are contained in a single 
glass of water. The iridescence or lustre of various fishes may 
be also caused by these animalcules attaching themselves to 
their scales. 
Besides the Ncreidce, there are many other sea-animalcules, 
minute Crustacea, MediiscB, Infusoria, and certain corallines possess- 
ing luminous properties, which, when congregated in shoals, 
give to the agitated waters that phosphorescent brilliancy 
observed by almost every navigator. It is difficult, however, 
in many of these instances, to say whether the luminance is the 
result of decay, or of a vital and peculiar principle. It may be 
remarked, however, that when the waves scintillate with bright 
green sparks, the light is owing to the presence of minute living 
creatures, and that, when the phosphorescence is steadier, and 
of a paler hue, the proximate cause is the decay of gelatinous 
particles with which the ocean abounds. 
The phenomenon happens most frequently in warm countries, 
and most brilliantly immediately after a few days of still weather. 
Now, though such would certainly be most favourable to the 
rapid increase of minute animals, it would at the same time be 
equally active in hastening the process of decay, so that, in the 
majority of instances, the phosphorescence of the ocean may be 
safely attributed to the decomposition of organic particles. 
From all the experiments which have been made, it would 
seem that animal luminance is a true phosphorescence, increased 
by warmth, and made most obvdous when the animal is disturbed 
or put in motion. In plants, it was surmised on fairly good 
grounds that electricity was sometimes the illuminating agency ; 
but in animals we have no such reason. 
The light occasionally yielded by plants seems to be in most 
cases the result of phosphoric emissions ; in some, it appears to 
arise froip the presence of electricity. In the former case, the 
phosphorus must be taken up from the soil, which is known to 
contain many phosphates ; in the latter, the plants seem to act 
as the mere conductors of electricity from one medium to 
another. On the other hand, luminance in animals seems in all 
cases to be owing to the presence of phosphoric matter ; nor is 
there any difficulty in accounting for its presence. In the dead 
