Sept. 17, 1885 | 
As an example of the Syllide, the common Zusyllis, so often 
mentioned by previous authors, may be taken. Under irritation 
a fine green light is emitted from the ventral aspect of each foot, 
and the scintillations seem to issue from many points at each 
space, flash along both sides of the worm posterior to the point 
of stimulation, and then disappear. Under severe irritation the 
animal remains luminous behind the injured part for nearly 
half a minute, while the surface of granular light on each seg- 
ment is larger than usual, and in some instances those of opposite 
sides are connected on the ventral aspect by a few phosphorescent 
points. The body behind the irritated region has a paler pinkish 
hue immediately after the emission of light showing that the 
luminosity is diffused. 
In the Cheetopteridee the phosphorescence is remarkably 
beautiful, bright flashes being emitted from the posterior feet ; 
but the most vivid luminosity is at a point on the dorsum between 
the lateral wings of the tenth segment. Here the abundant mucus 
exuded by the animal can be drawn out as bluish-purple fire of 
great intensity, which, besides, now and then gleams along the 
edges of the wing-like processes, and illuminates the surrounding 
water. A very characteristic odour, somewhat resembling that 
produced by phosphorus in combustion, is given out by the 
animal during such experiments. In this connection it may 
be observed that Quoy and Gaimard mention that an odour 
similar to that around an electric machine is given out by 
luminous marine annelids. 
Amongst the Terebellidze, as first shown by Grube none excel 
the genus Polyctvrus in the brightness of the phosphorescence and 
the ease with which it is elicited. Mere blowing on the water of 
the dissecting-trough suffices to cause in the British Polyczrrus the 
most vivid pale bluish luminosity, which gleams for a moment 
along every one of the independent mobile tentacles. Long 
before Grube, however, had discovered the phosphorescence of 
Polycirrus, our patient and laborious countryman, Sir J. Graham 
Dalyell, had noticed it in the group (“ Powers of the Creator,” 
vol. ii. p. 210), for he mentions that when irritated Zerebel/a 
figulus gaye out the most copious blue refulgence, intermingled 
with a reddish flame. Another member of this family, viz. 
Thelepus, is only faintly phosphorescent in life, but when decom- 
position has made progress it gleams in the vessel with a pale 
lambent light, somewhat like phosphorus in air. 
In the pelagic Tomopteridz certain peculiar structures on the 
parapodia, formerly supposed by some to be eyes, and by others 
simply glandular organs, were lately found by Professor Greeff 
(Zoologischer Anzeiger, 1882, p. 384—87) to be luminous organs, 
which, though glandular, have a considerable nervous supply, 
including a ganglion, 
Panceri’s observations on the luminous annelids of Naples, and 
the peculiar type Balanoglossus (Enteropneusta) have recently 
added considerably to our knowledge of thesubject. He specially 
describes, in Chetopterus, the structure of the phosphorescent 
glands in the great pinnules and other parts, which produce the 
luminous mucus. With some reason he concludes that two 
kinds of phosphorescence are present in annelids, viz., one which 
is the result of purely nervous action, and another which is due 
to this #Zs a luminous secretion. 
A Turbellarian, viz., Plamaria vetust1, was mentioned by 
Viviani ( Of. cif. p. 13) as luminous, but this feature appears to be 
rare in the group; and the same may be observed of phos- 
phorescent Rotifers, one of which (Syzchetla baltica) was de- 
scribed by Ehrenberg (Of. cé¢. p. 128).  Giglioli (Of. cit. 
p- 498) again, records a Sagztta which showed a feeble luminosity 
in the posterior region of the body. 
The minute forms amongst the Crustacea (chiefly Copepoda) 
were recognised as phosphorescent by Athanasius Kircher in 1640, 
and have been mentioned by most authors who have alluded to the 
subject since that date. Thus Viviani gives seven species from 
the shores of Genoa, and Tilesius no less than nineteen luminous 
crustaceans from Krusenstern’s voyage. Dr, Baird describes the 
light given out by those met with in his cruises as brilliant in the 
extreme, and Vaughan Thompson added considerably to our 
knowledge of Sapphirina and of the luminous schizopods, an 
example of which had been discovered by Sir Joseph Banks, and 
described by Macartney (P27. Trans. 1810, as ‘Cancer fulgens”’). 
Most authors agree that the minute forms, such as the Copepods, 
give a sparkling appearance to the surface of the water. The 
light in these, according to Lesson, proceeds from glands placed 
on the sides of the thorax; while Giglioli found the luminous 
organ of the cosmopolitan Sapphirina in the anterior part of the 
thorax. On the other hand, Captain Chimmo (Zuflectcila, 
NATURE 
479 
&c., 1878) thought it was decomposing food in the stomach, 
and Prof. Moseley (Of. cz#. p. 574.—Naturalist on the Cha/- 
Zenger’) in certain cases entertained a similar opinion. The phos- 
phorescence of the Euphausiidze was a prominent feature in the 
voyage of the Chadlenger, brilliant flashes being emitted on cap- 
ture from a series of spots along the trunk and tail. Mr. Murray 
also met with a diffused light in the Farée channel when dredging 
in the 7yz¢on, and he attributed this to the phosphorescent organs 
of Nyctiphanes norvegica, M. Sars, one of the same group. Prof. 
G. O. Sars describes these organs as composed of a series of 
coloured globules, the lens-like body of which acts as a condenser, 
and thus enables the animal to produce at will a bright flash of 
light in a given direction (“ Challenger Narrative,” Zoology, I. 
part ii. pp. 740—43). 
Marine phosphorescence has some of its most striking ex- 
amples amongst the Tunicates. One of the best known instances 
is that of Pyvesoma, the light from which has been so graphically 
described by M. Peron, Prof. Huxley, and other naturalists who 
have had an opportunity of observing it. It proceeds in each 
member of the compound organism from two small patches of 
cells at the base of each inhalent tube. These cells contain a 
substance resembling fat. Sa/sa has frequently been mentioned 
as a luminous form by many authors, but Delle Chiaje found 
that in the Mediterranean Salsa pinnata was not phosphorescent ; 
and amongst the multitudes of Salpze which for some weeks 
abounded at Lochmaddy in North Uist, neither the former nor 
the Sa/pa spinosa of Otto exhibited this property, though a spark 
was occasionally seen in the nucleus in some specimens, probably 
from the food. Giglioli likewise is doubtful concerning them, 
but in one instance a brilliant rose-coloured light appeared in the 
nucleus. Dodfolum, on the other hand, shone with a greenish 
tint, while examples of 4/fendicularvia which he encountered in 
yarious seas were chameleon-like in their luminosity, and often 
gleamed with great brightness. 
Various mollusks exhibit the property of phosphorescence. 
Fabricius ab Aquapendente mentions Sef/a, Panceri Zledone, 
Adler Chama and ‘‘ Ductylus.”’ The best known, however, is 
Pholas dactylus, which possesses two wavy bands and triangular 
organs of ciliated epithelium on the inner surface of the mantle. 
These secrete a luminous substance, soluble in ether and alcohol, 
which light up the excurrent water. The light is also main- 
tained for a long time during putrefaction, as in the case of 
Thelepus. Panceri found that carbonic acid extinguished the 
light, but that air re-illuminated it, just as Johannes Miiller had 
previously observed in a vacuum and in air. The light is mono- 
chromatic, the bands having a constant place in connection with 
the solar spectrum (from line E to line F). 
Several Pteropods likewise contribute to the phosphorescence 
of the sea. Thus Giglioli noticed that a Cleodora gave out a 
very reddish light, while a Crisezs and a Flyalea were lumi- 
nous at the base of the shell. He mentions also a large un- 
known Heteropod (Of. c7é. p. 497) in the Indian Ocean, which 
glowed with a reddish phosphorescence. Amongst the Derma- 
tobranchs, Phyllirrhoé has the same property, Giglioli further 
found that Zoligo sagitfatus and a small Octopus gleamed all 
over with a whitish luminosity. 
Phosphorescence in living fishes appears to have been ac- 
curately observed within a comparatively recent date, though the 
luminosity of dead fishes has been known from very early times, 
and has been the subject of many interesting experiments such 
as those of Robert Boyle on dead whitings (P/z/. Trans. 1667, 
pp. 591-93), and Dr. Hulme on herrings (Phil. Trans. 1800, 
p. 161). I do not mean to say that the literature of the so- 
called phosphorescent fishes is scanty, for it extends from the 
days of Aristotle and Pliny to modern times, but that the writers 
have had little reliable evidence in regard to living fishes to bring 
forward. Thus of upwards of fifty fishes entered by Ehrenberg 
in his list it is hard to say that one is really luminous during life. 
In many cases it is probable that the supposed phosphorescence 
of large forms, such as sword-fishes and sharks, has arisen from 
the presence of multitudes of minute phosphorescent animals in 
the water, just as the herring causes a gleam when it darts from 
the side of aship. Prof. Moseley, for instance, observed in the 
Challenger that when large fishes, porpoises, and penguins 
dashed through phosphorescent water, that it was brilliantly lit 
up, and their track marked by a trail of light. The same feature 
is observed in hooked fishes, and it is known that fishermen are 
doubtful of success when the sea is very phosphorescent, for the 
presence of the net in the water excites the luminosity and scares 
the herring. 
