LUMINOUS ANIMALS 
141 
exclusively, causes the phosphorescence of 
the sea is a form of life known as Noctiluca 
miliar is, a minute, spherical and jelly-like 
mass measuring about a thirtieth of an inch 
in diameter, upon the surface of which are 
numerous vein-like markings. It is only met 
with in waters adjacent to the shore, and 
calm, dark nights during the summer and 
autumn months are the most favourable times 
to observe its light, for should the sea be rough 
the tiny creatures get driven below the surface 
and become too scattered to produce much 
illumination. 
The intensity of the light emitted by these 
animals is so great that a glass full of them 
will produce sufficient illumination to enable 
a person to read at a distance of two feet away. 
Mr. F. T. Bullen gives an interesting account 
of the luminosity of the sea as witnessed by 
him during a voyage in the neighbourhood 
of the Philippine Islands. He states that the 
light produced was so intense that the stars 
looked merely like white points against a black 
sky, while the tracks of fishes were revealed 
by streaks of fire-like intensity, and the ship 
upon which he was journeying was encircled 
with bright light as the waves broke against 
the hull of the vessel. 
Darwin also tells us that: “ When sailing 
