428 THE INHABITANTS OF THE SEA. 
aid of the transparency, a number of little, elongated, narrow 
bodies (viscera), which also participated in a high degree in the 
possession of the phosphoric light.” 
In the Pholades or Lithodomes, that bore their dwellings in 
the hard stone, as other shell-fish do in the loose sands, the 
whole mass of the body is permeated with light. Pliny gives 
us a short but animated description of the phenomenon in the 
edible date-shell of the Mediterranean (Pholas dactylus) :— 
«It is in the nature of the pholades to shine in the darkness 
with their own light, which is the more intense as the animal is 
more juicy. While eating them, they shine in the mouth and 
on the hands, nay, even the drops falling from them upon the 
ground continue to emit light, a sure proof that the luminosity 
we admire in them is associated with their juice.” Milne-Edwards 
found this observation perfectly correct, for wishing to place 
some living pholades in alcohol, he saw a luminous matter exude 
from their bodies, which on account of its weight sank in the 
liquid, covering the bottom of the vessel, and there forming a 
deposit as shining as when it was in contact with the air. 
Several kinds of fishes likewise possess the luminous faculty. 
The sun-fish, that strange deformity, emits a phosphoric gleam ; 
and a species of Gurnard (T’rigla lucerna is 
said to sparkle in the night, so as to form fiery 
streams through the water. 
With regard to the luminosity of the larger 
marine animals, Ermann, however, remarks 
that he so often saw small luminous crustacea 
in the abdominal cavity of the transparent 
Salpa pinnata, that it may well be asked 
Short Sun-Fish. whether the phosphorescence of the larger 
creatures is not in reality owing to that of 
their smaller companions. 
According to Mr. Bennett, “ Whaling Voyage round the Globe,” 
a species of shark first discovered by himself is distinguished 
by an uncommonly strong emission of light. When the specimen, 
taken at night, was removed into a dark apartment, it afforded 
a very interesting spectacle. The entire inferior surface of the 
body and head emitted a vivid and greenish phosphorescent 
yleam, imparting to the creature by its own light a truly ghastly 
and terrific appearance. ‘The luminous effect was constant, and 
