79 PHOSPHORESCENCE. 
preceded by the division of the nucleus. Professor Allmann found 
that the seat of the phosphorescence is in a network lining the 
external structureless membrane. The production of phosphorescence 
is not continuous, some little rest being needed after a display of 
Juminosity. Alcohol excites the phenomenon strongly, as also do 
certain chemical substances. 
Marine phosphorescence in general by no means depends 
entirely on organisms of the class of Noctinuca. Again, it is 
astonishing how diverse are the living things of the sea in connection 
with which phosphorescence has been observed. Fishes, Medusz, 
Crustaceans, Annelids, and various Protozoa and Bacteria display the 
phenomenon. The luminous Scopelus, a bony and perfectly-organised 
fish, with steel-grey coloured scales, emits a phosphorescent light 
from the scales or plates covering the head and body, as well as from 
the circular depressions on the abdomen and sides, giving rise to an 
appearance like small bright stars. The luminous gleams, which are 
intermittent, entirely disappear after the death of the fish. The 
fact seems to rest on pretty good authority that many of the deep-sea 
fishes, living in depths of from 500 to 800 fathoms, are phosphorescent. 
Under certain circumstances many of the Crustaceans are 
luminous. The point from which the light emanates is not always 
ascertainable, but in some cases it comes from small globular organs, 
which on close examination prove to be a very complicated luminous 
apparatus, provided with a lens acting as acondenser. Some of the 
Corals (the PENNATULID2) shew the property of phosphorescence. 
The Annelids give off pale green somewhat steady scintillations 
of light at the attachment of each scale, and if the scale be separated 
gleams and pulsations of light are exhibited at the ruptured surface. 
Tremors in the water containing some of these phosphorescent 
Annelids will cause a vivid pale blue flash of light. Professor 
Panceri connects the phenomenon with certain fatty granules. He 
says that the luminous emanations have no connection with light or 
