104 
MARINE FAUNA OF ST. ANDREWS. 
already been noticed *; so that in the mean time the remarks 
shall be confined to the Polynoidte, three common species 
of which afford ready means of experiment. In Harmothoe 
imbricata irritation causes a series of bluish-green flashes 
at the points of attachment of the scales, and then a steady 
light for some time. Very pale specimens seem more irri¬ 
table than ordinary forms. No pulsations of light are ob¬ 
served on the phosphorescent surface of the detached scales. 
On the whole the light in this species is characterized by its 
steadiness. It does not readily emit its phosphorescence when a 
•ittle sulphuric ether is added to the water; nor does mechanical 
irritation in these circumstances cause any change in its mani¬ 
festation. Acetic acid acts as a poison, causing a momentary 
gleam as the scales are thrown off, which wholly disappears 
with the death of the animal and the ejection of the proboscis. 
If strong methylated spirit be gradually added to the sea¬ 
water (in a small vessel), there is seldom phosphorescence if 
no mechanical irritation occurs ; the animal perishes with all 
the scales on its back. The luminous emissions are similar 
when spirit is applied to the annelid in the air. Polynoe 
floccosa seems to be more irritable, and to emit its phosphor¬ 
escence more readily than the foregoing at the same points. 
When one of the scales is detached, the greenish light is 
given off as if in pulsations from the surface of attachment, 
somewhat quickly at first, then slower, and finally dis¬ 
appearing. In Evarne impar , again, the detached scales give 
off a flashing light, such as might be caused by a swift 
series of waves, and which quite differs in character from 
that in P. floccosa. 
The Gephyreans are not so abundant as on the muddy flats 
of the west and south, where swarms of the common forms 
are found in a single spadeful. The highly characteristic 
Echiurus vulgaris , however, occurs, often in great numbers ; 
and though Priapulus caudatus is not met with in the lit¬ 
toral region, nor so large as in the Hebrides, still it is 
not rare in deep water, and is frequent in the stomachs of 
fishes. 
* Ann. & Mag. Nat. Hist. 4th ser. 1872, vol. ix. pp. 6 & 7. 
