THE PHOSPHORESCENCE OF THE DEEP. 42] 
fathoms, were most brilliantly phosphorescent. In some places 
nearly everything brought up seemed to emit light, and the 
mud itself was perfectly full of luminous specks. The alcyo- 
narians, the brittle-stars, and some annelids were the most 
brilliant. The Pennatids, the Virgularie, and the Gorgonize 
shone with a lambent white light, so bright that it showed 
quite distinctly the hour on a watch, while the light from 
Ophiacantha spinulosa was of a brilliant green, coruscating 
from the centre of the disk, now along one arm, now along 
another, and sometimes vividly illuminating the whole outline 
of the star-fish. While the Ophiacantha shines like a star of the 
most vivid uranium green, the sea-pen (Pavonaria quadrangu- 
laris) is resplendent with a pale lilac phosphorescence like the 
flame of cyanogen gas, not scintillating like the green light of 
Ophiacantha, but almost constant, sometimes flashing out at 
one point more vividly, and then dying gradually into com- 
parative dimness, but still sufficiently bright to make every 
portion of the polyp visible. 
Such numbers of the Pavonaria were brought up at one haul 
of the dredge in the Sound of Skye, that the “ Porcupine” had 
evidently passed over a forest of them. While the darkness of 
winter frowns over the surface of the Northern Atlantic, the 
animated shrubs at its bottom are thus glowing with light, and 
a kind of magical day prevails in depths which were supposed 
to be shrouded with perpetual night. But it might have been 
better for many of the luminous denizens of the abyss if a more 
obscure existence had been their lot; for in a sea swarming 
with predaceous crustaceans with great bright eyes phosphor- 
escence must surely be a fatal gift. 
Off the coast of Portugal there is a great fishery of sharks 
(Centroscymnus Cololepis), carried on at a depth of 500 
fathoms. If an animal so highly organised as a shark can thus 
bear without inconvenience the enormous pressure of more 
than half a ton on the square inch existing at {hat depth, it 
is a sufficient proof that the pressure is applied under circum- 
stances which prevent its affecting it to its prejudice, and there 
seems to be no reason why it should not tolerate equally well 
a pressure of one or two tons, or why many other fishes—though 
FF 2 
