Ix THE SEA 351 
denly appear globes of soft and lambent light, 
given out perhaps from the surface of some 
large Medusa. 
“A beautiful white cloud of foam,” says 
Coleridge, “at momently intervals coursed by 
the side of the vessel with a roar, and little 
stars of flame danced and sparkled and went 
out in it; and every now and then light de- 
tachments of this white cloud-like foam darted 
off from the vessel’s side, each with its own 
small constellation, over the sea, and scoured 
out of sight like a Tartar troop over a wilder- 
ness.” 
Fish also are sometimes luminous. ‘The 
Sun-fish has been seen to glow like a white- 
hot cannon-ball, and in one species of Shark 
(Squalus fulgens) the whole surface sometimes 
gives out a greenish lurid light which makes 
it a most ghastly object, like some great 
ravenous spectre. 
THE OCEAN DEPTHS 
The Land bears a rich harvest of life, but 
only at the surface. The Ocean, on the con- 
