bristle-tuft®, perhaps, being more conspicuous than those which followed. The ventral
groove turned to the right behind the twenty-fifth scute. The two kinds of bristles, viz.,
those with winged, tapered tips and those with broad paddle-tips, are present throughout
the series, though best developed in the first eight. The hooks and their attendant short
penniform or beaked bristles occur throughout the entire anterior region. The branchiae
have the usual structure and their ocelli remain in the preparation. This example
demonstrates the wide range of segments in the anterior region of Sabellids, as, indeed,
various figures of previous authors show; thus Chenu1 gives one with eleven pairs of
thoracic bristles.
The setigerous processes are ranged along the lateral regions from the second
segment backward, a differentiation occurring anteriorly by the inflection of the groove
which often passes behind the tenth bristle-tuft to the mid-ventral line, though in others
it is further back. Each of the setigerous processes anteriorly has dorsally three longer
bristles with straight shafts, tips bent backward and moderate wings (Plate CXXVIII,
fig. 2). The edges of the wings appear to be minutely serrated. Following these is a
double series of comparatively stout bristles with short and broad wings, making a
spatulate tip with a filament in the centre (Plate CXXVIII, figs. 2 a and 2 b). These
bristles also have a dorsal curve, the filament trending in that direction, so that they
would brush an opposing structure with the convex surface. From the nature of the parts
the shafts are somewhat abruptly tapered at the tip. Some of the bristles have modified
tips so that they resemble a short and broad knife-blade, as in certain forms in Chsetopterus,
the shaft not being continued along the centre as in the ordinary winged types.
In the posterior segments the bristles alter, being shorter, fewer in number, and with
modified (geniculate) tips (Plate CXXVIII, fig. 2 c) which have moderately wide wings
at the base, but they soon diminish, and the long central tapering tip projects far beyond
them, thus performing the functions of the simple bristles of this region in other forms.
The anterior rows of hooks are below the setigerous processes, and consist of a long
series of the avicular forms (Plate CXXVIII, fig. 2 e) with serrated crowns sloping to the
sharp main fang, a rather long, slightly striated neck with straight sides, the anterior
outline curving forward into the rounded prow and the posterior into the well-marked
basal process. Accompanying each is a bristle (Plate CXXVIII, fig. 2d), the shaft of
which has a curvature toward the distal end, and the tip has a region with short wings
so modified as to resemble a hook with a long shaft and a main fang.* 1 2 Two forms of
accompanying bristles thus are present in this species, viz., those with broadly spatulate
tips, and those with a slightly enlarged posterior crown and a beak-like point anteriorly
nearly at right angles to the shaft. In a small example from Perelle Bay the latter
was large and with distinct wings (as in fig. 2 d). The hook has a larger space between
the main fang and the prow than in Sdbellct penicill/ns.
The hooks behind the foregoing region are above the setigerous processes, and they
become fewer and fewer as well as smaller, and with a longer base in their progress
toward the tail (Plate CXXVIII, figs. 2 ƒ, 2/1).
1 ‘ Illust. Conch./ 11® livr., pi. vii, fig. 6.
2 So far as can be seen at present certain specimens do not have the very broad paddle-like
bristles, though their hooks cannot be differentiated from those which have these broad bristles.
The tube is a tough horny secretion of an olive-brown hue, and the exposed parts
are covered with minute sand-particles, whereas the sheltered portions are hyaline and
more delicate. In withdrawing its branchise it not only rolls the filaments together, but
the elastic anterior end of the tube doubles over or is rolled into a coil (Plate CXIX,
figs. 11 and II"). In the G-ouliot Caves of Sark the tubes occur in numbers under the
coating of Balani so abundant there, a.nd their devious windings are characteristic.
Habits.—It bores a hole th rough as well as passes along between the layers of
Balani and lines the interior with its tough secretion. It further invades the cracks and
fissures of the rocks near low water-mark. It is also partial to bivalves of various kinds,
such as Pecten pusio, and pierces masses of Cellepova, besides either piercing ascidians and
sponges or being coated with them. In the same oyster-shells are found the boring
sponge and the boring mollusk Gastrochcena. The perforations in the calcareous
masses are circular, and though more or less curved and coiled, are not to be confounded
with those of Dodecaceria and Polydora. Large ascidians also surround the tube, but
probably they were developed round it instead of being perforated. No trace of acidity
is found in the body except at the tip of the tail, where a distinct acid reaction occurs,
but whether this is connected with tube-formation or boring is unknown.
It is possible that the Amphitrite Flacherformige (Nierenformige) of F. H. W. Martini1
refers to this species. His A. Besenformige (Pinsel des Kolumnus of Naples) is less
easily discriminated.
R. Wagner2^ (1832) gives Hie synonymy of this species from Nizza as Sabella
rentilabrum, and describes the alimentary canal as having two sacs in front, probably
referring to the anterior nephridia or “ muciparous” glands. He likewise shows a
portion of the ventral ganglionic chain with its lateral branches and commissures;
Sars (1861) found in the northern forms six or seven bristles with longer tips in
the anterior tufts instead of the three usually present in the British examples, and in the
same way a larger number of spatulate forms (twelve to twenty), whilst posteriorly the
number was ten to sixteen. He gives the number of branchial filaments as ten to
fourteen pairs, their length as one-sixth that of the body, and with purple ocular points
five to eleven in number distributed on the dorsal base of the filaments. He states that
the collar has a lateral as well as a dorsal and ventral fissure—“ lateraliter profunde
incisum seu bilobum.” This differs from the condition in the British forms. His
examples ranged from 1^ to 2 inches in length, and they frequented water 10 to 30 fathoms
in depth amongst Nullipores, Balani and Pecten Islandicus.
Leuckart . (1819) was the first to recognise that Muller’s “ nierenformigen
Amphitrite ” was probably distinct from Sabella penicillus, when examining three
examples from Iceland, and he gave a careful account with figures which show that
The broadly spatulate belong to the typical form, and no eyes are present. Those with narrower
wings come from Berehaven, Ireland, and show no eyes. Other varieties are AB from Herm, and W
from Guernsey. Potamilla Torelll has rather broad wings to its spatulate bristles, and may yet be
linked on to this form.
1 * Allg. Geschichte der Natur/ vol. ii, 1775, p. 483, Taf. Iv, fig. 3.
2 ‘ Isis/ 1832, p. 655, Taf. x.