478 
NATURE 
a eg f* ay “ae 
[ Sept, 17, 1885 
the stomach, and that these are chiefly composed of cells con- 
taining a substance of a fatty nature, the oxidation of which 
causes the light. Panceri’s conclusions further considerably modify 
Forbes’s views about the direction of the waves or points of 
lizht. He supposes that the elements which stand in the place 
of nerves are capable of producing in the luminous batteries of 
the polyps a momentary oxidation—more rapid and more intense 
—accompanied by phosphorescence. Like those examined by 
Professor Milnes Marshall (‘* Report on the Oban Pennatulidz,” 
p. 49, Birmingham, 1882), the specimens at St. Andrews, after 
irritation, show aseries of brilliant coruscations which flash along 
the rows of polyps in a somewhat irregular manner. 
Two other Alcyonarians, /unicv/ina and OUmbellularia, are 
equally phosphorescent. Though the former is familiar enough 
to some of the long liners of the outer Hebrides and west coast, 
it is rare that either is procured for scientific investigation. 
Funiculina quadrangularis, according to Forbes (Johnston's 
Brit. Zooph. vol. i. p. 166), gives out a vivid bluish light, which 
comes from the bases of the polyps, and appears to be connected 
with the reproductive system. Wyville Thomson (*‘ Depths of 
the Sea,” p. 149) describes the specimens procured in the Por- 
cupine as resplendent with a steady pale lilac phosphorescence 
like the flame of cyanogen; and always sufficiently bright to 
make every portion of a stem caught in the tangles distinctly | 
visible. The same zoologist mentions that the stem and polyps 
of Umbellularia axe so brightly phosphorescent, that Captain 
Maclear found it easy to determine the character of the light by 
the spectroscope. It gave a restricted spectrum sharply included 
between the lines 4 and D (‘‘ Atlantic,” vol. i. p. 151). 
Besides the foregoing Alcyonarians, /s¢s and Gorgonta have | 
been indicated as likewise phosphorescent. Dr. Merle Norman 
and Dr. Gwyn Jeffreys (whose death since the last meeting of 
the British Association is a serious loss to science) mention a 
beautifully luminous /s¢s on board the French ship Ze Travazl/eur; 
and Sir Wyville Thomson (‘‘ Atlantic,” vol. i. p. 119), with the 
facile and genial pen which characterised the lamented naturalist, 
gives a fascinating picture of a long, delicate, simple Gorgonian 
| 
which came up in immense numbers in the trawl from 600 | 
fathoms off the Spanish coast. He conjures up this Gorgonian 
forest as an animated cornfield waving gently in the slow tidal 
current, and glowing with a soft diffused phosphorescence, scin- 
tillating and sparkling on the slightest touch, and now and again | 
breaking into long avenues of vivid light, indicating the paths 
of fishes or other wandering denizens of these enchanted regions. 
Piof. Moseley thinks that this brilliant phosphorescence of the 
Alcyonarians may be regarded as an accidental production, but 
that it may be of occasional service. Further, that the deep sea 
is at any rate lighted up by these Alcyonarians, which would 
thus form luminous oases round which animals with eyes might 
possibly congregate (‘‘ Notes of a Naturalist on the Challenger,” 
Pp. 590). 
The last group of the Ccelenterates, the Cvenophora, are even 
more conspicuous than the foregoing in regard to luminosity. It 
is indeed long since the Abbé Dicquemare descanted on Cydippe 
(Pleurobrachia) and Suriray on Bereé, while subsequent authors 
have made it clear that the majority of this group are phos- 
phorescent. 
at various stages is one of the most prominent luminous forms 
during certain seasons. Their enormous numbers make their 
effects more striking, though the intensity of the phosphorescence 
is less than that of the Medusee. Quiet seas like Bressay Sound 
and the Firth of Forth are occasionally covered by a dense 
layer of these animals. Prof. Allman found that Bero# did not 
phosphoresce if suddenly taken from light into darkness, but 
that after they had remained about twenty minutes in obscurity 
they became luminous. Considerable variety exists in this 
respect at St. Andrews, some emitting light at once, others 
showing none. It is probable that this uncertainty is connected 
with the hygienic condition of the individuals. 
In foreign seas many brightly luminous species are met with. 
Thus Prof. A. Agassiz (‘‘ North American Acalephz,” p. 20, 
Cambridge, 1865) describes Mnemiopsis Leidyi as “ exceedingly 
phosphorescent, and when passing through shoals «f these 
Medusve, varying in size from a pin’s head to several inches in 
length, the whole water becomes so brilliantly luminous that 
an oar dipped up to the handle can plainly be seen on 
dark nights by the light so produced; the seat of the phos- 
phorescence is confined to the locomotive rows, and so excee1- 
ingly sensitive are they that the slightest shock is sufficient to 
make them plainly visible by the light emitted from the eight 
phosphorescent ambulacra.”” The same author (Of. cit. p. 24) 
mentions that Zesz-arza has a very peculiar bluish light of an 
exceedingly pale steel colour, but very intense. Giglioli, again, 
found that the beautiful riband-like Cestus shone with a reddish 
yellow light, but in Zucharis the latter was intensely blue 
(Of. ct. p. 495, 495). 
While many of the preceding group are pelagic at all periods 
of their existence, the luminous star‘fishes are in their adult 
condition members of the bottom fauna. The larval stages of 
the brittle-stars, however, are passed at the surface of the water, 
where it is probable they add their quota to swell the ranks of 
the phosphorescent types. Amongst the first to note this 
property in the brittle-stars was Prof. Viviani, who found on the 
shores of Genoa a little brittle-star which he termed Asterias 
noctiluca,+ and which probably is identical with the Amphiura 
elegans of Leach. Peéron likewise mentions the phosphorescence 
of his Ophiura phosphorea. Sir Wyville Thomson observed in 
the Porcupine that the light from Of/iazantha spinulosa was of 
a brilliant green, coruscating from the centre of the disk along 
the rays and illuminating the whole outline of the starfish 
(‘Depths of the Sea,” p. 98). More recently Prof. Panceri 
of Naples has re-examined the phosphorescence of the species 
described by Viviani, and he finds that though with the first 
momentary glow the whole ray is lit up with a greenish light, 
that the luminous points correspond with the bases of the 
pedicels and are ranged in pairs along the arms (d/“i della R. 
Accad. d. Sc. Fisiche e Mathem. di Napoli, 1875, p. 17, pl. iv. 
figs. 1, 3). In deep water (between twenty and forty fathoms) off 
our eastern shores, Ophzothrix gleams all over the trawl-net with 
a pale greenish light; but the adults of the same form between 
tide-marks give no trace of luminosity. 
The older authors were familiar with certain luminous 
annelids which they termed MVereides, such as Verets phos- 
Phorans. Ehrenberg paid considerable attention to this group, 
specially referring to Polynoé fulgurans from the North Sea, 
Nereis noctiluca® and Nereis (Photocharis) cirrigera, the latter 
species having a photogenic structure in its cirri like the electric 
organ of the Torpedo. The latter form is probably related to 
the ubiquitous #zs;Z/’s, which, under various names, has been 
noticed by many observers. Thus it is very likely the same 
species that is mentioned by Harmer, in Baker’s ‘‘ Employment 
for the Microscope,” p. 400, as having been found on oyster shells ; 
and also by Vianelli, who describes it as a caterpillar-like form 
amongst seaweeds. Indeed the Syllideans have been conspicu- 
ous in the literature of phosphorescence from the time of De la 
Voie (1665, fe Panceri), and Vianelli (*‘ Nuove Scoperte intor- 
no le Luci dell’ Acqua Marina,” Venezia, 1749), to the recent 
period of Claparede (‘‘Glanures Zootomiques,” p. 95) and 
Panceri (O/. czt. p. 8). The structure of the cirri of the phos- 
phorescent forms, however, gives no support to the opinion of 
Ehrenberg that they possess a special photogenic structure. 
The luminous annelids group themselves under five families, 
| viz. the Polynoidze, Syllide, Cheetopteride, Terebellidz, and 
| Tomopteridz, and the number may yet be extended to include 
| other pelagic types. 
In our own ‘seas, as Prof. Allman observes, Bevoe | 
In the first family one of the most abundant is Wa mothoé 
7nbricata, which lives both between tide-marks and deep water, 
and is cosmopolitan in geographical distribution. It discharges 
| bright greenish scintillations from the point of attachment of each 
dorsal scale ; and thus, under irritation, the flashes are arranged 
in pairs along the body, or in a double moniliform line. If — 
severely pinched the worm wriggles through the water, emitting 
sparks of green light from the bases of the feet. The separated 
scales also continue to gleam for some time, chiefly at the sur- 
faces of attachment (scars), near which, in each, a ganglion 
exists. The same phenomenon is readily produced in a fragment 
either of the anterior or posterior end of the body. No mucous 
secretion is emitted, but the light is clearly produced by the will 
of the animal, and by the agency of its nervous system. A 
| recent writer, Dr. Jourdan (Zoologischer Anzeiger, March, 2 
1885, No. 189, p. 133), has endeavoured to prove that this 
luminosity in another member of the Polynoidze (viz., Polynoé 
torguata) is produced by cells secreting a phosphorescent mucus, 
but this view is by no means applicable in all cases. 
Besides the species mentioned, various other forms in this 
family are equally luminous, such as Polynoé scolopendrina, 
Achloé astertcola, Polynoé lunulata, and a Zetlandic Zznoa. 
1 ‘*Phosphorescentia Maris,” Genoa, 1805. p. 5, tab. i. figs. 1, 2 He 
observes: ‘‘Species hee radiatz instar stellz scintillas in marinis aquis 
excitasse, quas electrico fluido adscripserunt, admodum probabile est.” 
= Supposed by some to refer to Noctrluca miliaris. 
