i8 
COLOUR IN NATURE 
CHAP. 
Among Echinoderms phosphorescence seems to 
be known only among the Ophiuroidea, where it has 
been described both in Mediterranean and in Atlantic 
species. 
Among the Crustacea phosphorescence is exceed¬ 
ingly common, especially among deep-sea forms. In 
some cases the luminosity is confined to the eyes, in 
others, as in many of the deep-sea Schizopoda, there 
are special luminous organs placed behind the eyes 
or above the legs, in other cases again the phosphor¬ 
escence is diffused. 
In the terrestrial Anthropods phosphorescence is 
known among various insects, glowworms, fireflies, 
etc., and among centipedes, but it is not so common 
as among marine forms. 
Among the Mollusca phosphorescence occurs 
among pelagic forms such as Phyllirhoe , and among 
burrowing forms such as Pholas , whose luminosity 
has long been known. 
Next to the Coelentera theTunicata are perhaps the 
forms which display the most universal and brilliant 
phosphorescence. Every one knows Moseley’s de¬ 
scription of the brilliancy of the light emitted by 
Pyrosoma , the phosphorescent fire-flame. Many 
other pelagic Tunicates display the same pheno¬ 
menon to a lesser degree. The Tunicates display so 
many striking analogies to the Coelentera that this 
physiological one is perhaps not remarkable. 
Finally, we have the phenomena of phosphores¬ 
cence admirably displayed in fishes, especially the 
pelagic and abyssal forms. In the pelagic forms 
the sense-organs and the lateral line are often phos¬ 
phorescent, while in some cases there are special 
