(Plate CXXVa, figs. 4, 4 a, 4 b) are bound firmly together in flattened fascicles, slope
outward or obliquely upward and outward, and have a pale golden hue. They Lave
a pale base, a shaft with fine stride internally, and a tapering tip with a double wing,
the latter being obliquely striated (Figs. 4 and 4 a) and serrated on the edge. Moreover,
in old preparations the distal ends of these bristles break up into tufts of fine fibres.
The first tuft is smaller and the translucent tips less definitely formed than those which
follow, but the structure is essentially the same. The second series of bristles in each
tuft is considerably longer than in the previous forms (e. g. P. nesidensis), the tips almost
reaching the commencement of the wings of the distal series. Dr. Williams states that
the number of bristle-bundles on each side is sixteen, but he had probably omitted the
first. In transverse section the central region of the bristle presents the aspect of
severed fibres. Marenzeller and De St. Joseph mention a small papilla b'elow each
setigerous process in segments 6, 7, 8 and 9. Such is observed in some examples from
the second bristle-tuft backward to the third or fourth.
From each setigerous process an elongated and somewhat elliptical eminence having a
double row' of golden hooks along the centre passes ventrally. Each hook (Plate CXXVa,
fig. 4 c) has a stout base which narrows upward to the curved neck, above which are
the chief fang and two teeth on the crown, in a diminishing series in lateral view. Curved
striae extend downward from the small teeth on the crown. The basal part of the hook
is marked by radiating striae. In the anterior hooks the third tooth on the crown is less
distinct than in the posterior. In front view two teeth occur in the middle. The double
rows are so arranged that the hooks lie back to back with the fangs pointing outward.
The one set may by fixing arrest the egress of the animal, and the other may in the same
way stop ingress. In some of these rows sixty-six hooks occur on one side and sixty-
seven on the other, and in a second sixty-two and sixty-four respectively, so that the
combined effect must be considerable. The rows are somewhat longer in front, and the
first (opposite the second bristle-tuft) has only a single series of hooks. The anterior
rows also have the glandular wedge which dorsally envelopes the bristle-tuft, and has its
apex about the middle of each interspace. By-and-by, however, this glandular tissue
diminishes to a narrow longitudinal belt between the last six bristle-tufts, the shortened
eminence for the hooks touching the base of the bristles. With the cessation of the
bristles the rows of hooks are confined to the lateral uncinigerous lamella, which
continue to the posterior end, gradually diminishing in size as the slender tail is reached.
The lateral glandular belt is also continued from the bristled region backward between
the hook-lamellss, but stops short of the tail. On these uncinigerous processes the hooks
form a single row along the anterior edge, and at one end of the row a series of imperfect
hooks make a curve, those least developed having only a striated main fang, whilst those
touching the complete series show a crown above the fang, the base of the hook being
absent. The minute processes on the tail have few hooks.
The hooks of specimens from the Channel Islands show the two teeth above the great
fang very distinctly, and so with those from Shetland. The anterior hooks of those from
Lochmaddy have considerably shorter necks than those from St. Andrews. The striae on
the neck of the hook are well shown in those from Cornwall. De St. Joseph observes
that the first six thoracic rows have a single row of ninety to one hundred hooks.
Reproduction.—The development of this species has been worked out by Claparède
(1863) from a larval form 0'26 mm. long to a fairly late stage with two branchiae, whilst
the same author and Mecznikow filled in the earlier stages in what is probably the same
form (their Terebella Meclcelii.) Neapolitan examples are mature in August and September
(Lo Bianco). Southern (1914) dredged young specimens in May on the west coast of
Ireland.
Pallas examined the anatomy of this form and his account was fairly accurate, though
in regard to the reproductive organs he thought that the ovary terminated by a medial
orifice at the edge of the first abdominal band.
Claparede’s 1 (1863) youngest stage in the development of Lanice conchilcga occupied its
pelagic tube, and had seven segments, but was only 0-26 mm. in length. It showed a
horse-shoe-shaped anterior end with mouth and lower lip, a clavate median tentacle and
an eye on each side. The two segments Succeeding the cephalic plate were devoid of appendages,
but the fourth had a process on each side with two bristles, and, moreover,
contained circular sense-organ (his Gehörblasen). The next segment had a setigerous
process and two bristles as well as a flask-shaped ventral cirrus, and the following (sixth)
had only the latter. The terminal segment had palpocils and cilia at the vent. The
oesophagus, stomach and intestine were distinct. He followed the development through
various stages up to one with fifteen pairs of bristle-bundles, but still in the transparent
tube. The median tentacle of this was very long, and three others were developing at
each side. The statocyst had advanced forward and the two segmental organs were in
front of it, the author considering these were glandular organs for secreting the tube.
The flask-shapèd ventral cirri extended from the third bristle-tuft for twenty segments.
Between this stage and a young form of 5 mm., in which most of the adult characters
except the third branchia were present, there is a gap, for the four eyes of the younger
form have disappeared, and a series in a row behind the collar have taken their places.
In the same way the flask-like ventral cirri with a hook at thé tip have vanished and
tori are in position. Many segments are present, and the tentacles stretch beyond the
posterior end of the body.
At St. Andrews young forms occur in tubes on the blades of Laminaria digitata at
low water, and they keep up a wavy series of contractions of the body. The same were
met with on the laminarian blades in Lochmaddy.
The tubes vary considerably in composition according to locality, and the fimbriated
anterior end is not always present. Some are covered with diverse fragments of
bivalve shells which often have the pearly surface exposed, thus blending the lustre
of Nucida and Trochus, the white of the cockles, the pink of Tellina, the purple of
Donax, the brown and purple of mussels and other sea-worn fragments with entire
but minute univalves and many Foraminifera. These are mingled with pieces of gravel,
fragments of the spines of sea- and heart-urchins, fragments of the tests of the two
latter, and of Balani and Serpulæ. Other tubes are mainly composed of the hyaline
secretion with few sand-particles, or are chiefly made up of fine grains of gravel mixed
with the tests of Foraminifera, whilst a third series are curiously thatched with
fragments of the spines of Amphidotus mixed with minute Foraminifera and fragments
1 ‘ Beobach. Anat. Entwickl./ p. 72, Taf. viii, figs. 12 and 13, Taf. ix and Taf. x, figs. 1—8.