1048 REPORT—1885. 
spond with the bases of the pedicels and are ranged in pairs along the arms. In 
deep water (between 20 and 40 fathoms) off our eastern shores, Ophiothrix gleams 
all over the trawl-net with a pale greenish light; but the adults of same form he- 
tween tide marks give no trace of luminosity. 
The older authors were familiar with certain luminous annelids which they 
termed Nereides, such as Nereis phosphorans. Ehrenberg paid considerable atten- 
tion 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. This form 
is probably related to the ubiquitous Lusyliis, which, under various names, has been 
noticed by many observers. Thus very likely it is the same species that is men- 
tioned by Harmer, in Baker’s ‘Employment for the Microscope,’* 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 conspicuous in the 
literature of phosphorescence from the time of De la Voie,* and Vianelli,> to the 
recent period of Claparéde® and Panceri.’ 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 Polynoide, 
Syllide, Cheetopteridz, Terebellidee, and Tomopteride, and the number may yet 
be extended to include other pelagic types. 
In the first family one of the most abundant is Harmothoé imbricata, which 
lives both between tide-marks and in deep water, and is cosmopolitan in geographical 
distribution. It discharges bright greenish scintillations from the point of attach- 
ment 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,’ has endeayoured to prove that this luminosity in another 
member of the Polynoide (viz., Polynoé torquata) 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 astericola, Polynoé lunulata, and a 
Zetlandic Eunoa. 
As an example of the Syllide, the common Zusyllis, so often mentioned by pre- 
vious 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 segment 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 Cheetopteridz 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 
1 Atti della R. Accad. d. Se. Fisiche e Mathem. di Napoli, 1875, p. 17, pl. iv. fig.1-3. 
? Supposed by some to refer to Noctiluca miliaris. 
* Page 400. 
4 1666, fide Panceri. 
5 Nuove Scoperte intorno le Luci dell? Acqua Marina. Venezia, 1749. 
& Glanures Zootomiques, p. 95. 
7 Op. cit. p. 8. 
® Zoologischer Anzeiger, 2 March, 1885, No. 189, p. 133. 
