golden curved needles which project far beyond the others and so in one from Wales
kindly sent by Arnold Watson. Fauvel specially alluded to this variety, which he has
courteously termed var. Intoshi in his recent able memoirs on the Polychaets of St.
Thomas and those of Madagascar, and he has given figures of the paleas and hooks
(Plate VIII, figs. 50—53). His diagnosis is: Paleas of the external row of the operculum
with large teeth, without the long median process; paleae of the middle row short, hoodshaped.
Other characters as in the type. This author1 also describes another variety
viz. var. Gravieri, from the same island, in which the outer row of paleae corresponds with
the foregoing, but those of the inner row are alternately long and short. A curious
variety was found in its tube attached to Gellepora off St. Peter Port, Guernsey, in which
the external paleae had the distal central process reduced, so that at most it is only bifid
or rarely trifid. The blade is short and broad. The bill-hook series of the second row
is also broader and shorter than normal, but the inner paleae (third series) do not
materially differ. This form shows that the paleae are hollow, formed of two thin plates
of a somewhat brittle chitinoid substance.
On separating the lobes of the crown the mouth opens in the centre, and it is marked
by the same madder-brown pigment, sometimes showing longitudinal stripes on its dorsal
edge. It forms a large antero-posterior opening ventrally, the extended sides of which
bear six series of purplish tentacles, whilst posteriorly a deep groove lies between a
smooth fold on each side. Each series of tentacles springs from a base, as if formed of a
transversely folded sheet of tissue on each side, the purplish-brown pigment penetrating
between the folds and rendering them more distinct. The folds are directed obliquely
outward and forward, two on the pillars of the crown being more nearly longitudinal
than the others, and, besides, a patch of tentacles closely abutting on the fissure lies to
the inner side of these.
In a decomposing example Mr. Watson removed the superficial tissues of the
tentacles with a camel’s hair brush, leaving “ the skeletogenous shaft, which then appeared
as a transparent tube enclosing the muscular sheath of the central canal.”
The tentacles are long and nearly cylindrical filaments which in life often twist and
wriggle about. When stretched out they become attenuate, and distinct crenations
directed toward the tip occur on their ciliated edges, giving the organ a transversely
streaked aspect. Each contains two vessels, apparently a single trunk bent upon itself
at the tip, the trunks looping together at the bases of the tentacles. The fluid in these
vessels is perfectly translucent and free from granules. The matrix of the process is
granular and pale (hypodermic), and seems to keep the vessels from undue pressure, yet
retaining sufficient elasticity. Muscular fibres, both longitudinal and circular, are also
present, but the latter were not distinctly made out. Under a power of 60 diameters the
cilia of these organs are often seen to remain perfectly still, projecting from the sides
like minute glassy spikes; then they suddenly are adpressed, the points directed toward
the tip of the tentacle. Occasionally they are jerked in various ways, some vibrating
rapidly a few times and again becoming rigid. In the quiescent condition they bear
some resemblance to the spinous ray of a starfish or to some spine-clad stems like
Gleditschia. The tip of the tentacle is more opaque than the rest, from its granules and
1 ‘ Arch. Zool. Exper./ t. liv, p. 142, pi. viii, figs. 42—49.
gland-cells, and now and then it assumes a clavate outline, and in the preparations a few
show a slight constriction below the tip.
On each side of the posterior groove of the mouth with its glandular folds is a bifid
process, the anterior rounded portion of which is applied to the soft external fold of the
mouth, whilst the pointed and somewhat ligulate process projects, like a ventral branchia,
downward and slightly forward. These organs probably act in conjunction with the
posterior buccal groove in tube-formation.
The body (Plate CXII, figs. 1—1 e) is somewhat flattened, marked dorsally and
ventrally by a red streak. The cuticle is delicate and iridescent dorsally between the
branchiae, and is ciliated, especially over the sites of the blood-vessels. The dorsal groove
over the buccal region is also ciliated. Transverse rows of very long cilia also occur
behind the stomach and produce currents directed anteriorly. The ventral surface is
likewise ciliated and aids in the driving of the current forward, the water being expelled
anteriorly by undulatory movements of the body. Ingoing and outgoing currents are
visible at the mouth of the tube (Arnold Watson).
Arnold Watson has observed that the contents of the large muscular organ or
gizzard (Fig. 139, pv.) at times receive careful treatment before passing into the intestine,
sometimes being forced into the dark part of the adjoining oesophagus, or into the first
part of the intestine, but returned to the gizzard for further treatment.
On the ventral surface opposite the second and third segments is a smooth ovoid
area clearly differentiated from the surrounding parts by an elevated border.
Arnold Watson finds that the peristomial membrane is less developed than in
S. alveolata, and thus the median cirrus is able to hold its own.
The firm cylindrical region, which splits in front to form the two pillars of the
crown, has at its posterior border several processes, which apparently pertain to the next'
segment.
Dorsally (Plate CXII, fig. 1) is a pair of* branchiae of the normal shape, and from
them a fold passes ventrally on each side, a space, however, intervening between it and the
outer limb of the bifid postoral process. At the end of this ridge is a broad, flattened,
pointed lobe or papilla, and sometimes two occur. Such would appear to indicate the
first foot of the anterior or thoracic region of the body, more especially as on each side
of the mid-dorsal groove a tuft of three long simple bristles (Plate CXXIII, fig. 2 c), with
striated shafts and translucent tapered tips embedded in the tissues, passes forward to the
anterior crown. The inner bristle on each side forms a pair with its neighbour, and the
tips are slightly incurved towards each other ; the second and third (outer) are smaller.
These bristles pass forward in a nearly parallel manner, only very slightly widening in
front. The most interesting feature, however, is the occurrence to the exterior of these,
also embedded in the tissues, of several types of the modified bristles in the paleal
crown. Thus the slipper-shaped kind with the shaft coming off at an angle, the form
resembling a broad and short bill-hook, and the broad paddle-like external paleas with
the lateral spikes and special central process, are each represented on one side or
the other.
Mr. Watson notes that in the first segment the bristles are on the dorsal side of
the cirrus, the latter being between them and the building organ. In the second the
H i