and one half inserted in the tissues, the shafts dilating a little from the base, then
remaining cylindrical till the commencement of the very narrow wings, which have
minute striee directed outward and upward, after which they taper to a fine hair-like
curved tip. They thus appear to represent the first stage of the development of wings
on a bristle. The bristles slope outward and backward in the preparations, but' are
directed forward in life, the convexity of the terminal curve being in the same direction.
The shorter forms often alternate with the longer, and their number corresponds nearly
with that of the longer, viz. six in each tuft. There is also a slight gradation in the size
of the longer bristles from the dorsal to the ventral edge. Below each bristle tuft is a
row of hooks with elongated curved shafts (Plate CXXVII, fig. 4), which increase from
the base upward to the shoulder, above which the neck is distinctly narrowed, the head
again expanding so as to resemble with the main fang a bird’s head. Above the main
fang the rounded crown has a series of four to five smaller teeth. This kind of hook is
characteristic of the bristle-bearing segments.
A series of vertically flattened uncinigerous 1 amelias occur on the succeeding segments,
and some are broader at the tip than the base. They bear at their apices a row of
minute avicular hooks (Plate CXXVII, fig. 4 a), having short, broad basal processes with
a convex inferior outline, a posterior outline 'in which a deep sinus occurs above the
basal process, and an anterior outline which in some has a trace of a process bfeneath the
main tooth. The latter is of moderate size, but the teeth above it are proportionally
large, so that this hook does not present the same disproportion between the first and
succeeding teeth present in the long anterior hooks. In lateral view four to five teeth occur
above the chief fang, and in reality they form a rounded crown with their points curved
obliquely downward. Malmgren, while noting the distribution of the hooks from front to
rear, does not sufficiently define the structure of the posterior hooks.
Habits.—It has the appearance and habits of a tubicolar species, yet no tube was ever
found with it on the West Coast. It is possible that there it lives in a tunnel in the mud.
In other localities the tube consists of tough mucus, often with external shreds, or minute
grains of sand attached to it.
The T. massiliensis of Marion from Marseilles has only three teeth in the posterior
hooks, and the rostrate hooks extend to the sixteenth setigerous segment. Possibly this
is only a southern variety of T. glacialis. Then, again, the Octobranchus Giardi of Marion
and Bobretzky1 would appear to be closely allied to T. glacialis, except for the four pairs
of branchiae, which occur as simple processes from the segment bearing the eyes and the
three following. The hooks are similar. This form would appear to be an intermediate
type, especially in branchiae, between Trichobranchus and Terebellides (Hessle). The Fili-
branchus roseus of Malm has two pairs of simple branchiae and seventeen bristled segments.
De St. Joseph (1894) describes twenty eye-spots on each side, and he found three
pairs of segmental organs respectively in segments 3,4 and 5, the second pair being larger
than the others. He could not make out the three posterior pairs mentioned by Meyer.
The alimentary canal agreed with that in Amphi trite. His example, however, was young
and incomplete.
Hessle (1917) distinguishes Trichobranchus glacialis from T. roseus by the fact that
1 ‘ Ann. Sc. nat./ 68 ser., t. ii, p. 87, pi. x, fig. 21, and pi. ii, fig. 21 A and B.
the latter has no eye-specks, and only two pairs of branchim, whilst the nephridia occur
in the third, fourth, fifth and sixth segments.
Malmgren instituted the sub-family Canephoridea for Terebellides, in which a single
■ quadripartite branchia occurs. The hooks are rostrate in the anterior region, pectiniform
in the posterior region.
Genus CXL.—Terhbellides, Sars, 1835.
Cephalic lobe rounded-ovate, the plate being deeply frilled, and having a long and
smooth dorsal surface arising from a groove marking it from the first segment, and
ventrally being continuous so as to surround the mouth. The surface is covered by a
■ dense series of grooved tentacles. It is fused with the buccal segment.1 Under the
mouth is a large bilobed plate. Body enlarged anteriorly, tapering gently backward and
terminating in a moderately slender tail with the crenate anus at the tip. Dorsal surface
smoothly rounded; ventral surface is less rounded and posteriorly is flattened. Behind
the mouth and the cephalic plate which bounds it is a large semicircular flap or lamella
passing from side to side. Five distinct glandular belts on the ventral surface anteriorly,
and a belt in the line of the setigerous and uncinigerous processes. Branchim arising
from a single powerful stem on the second and third segments, and having four divisions—
two larger dorsal and two smaller ventral. Each has a smooth basal process or arm above
which are a dehse series of lamellae, which in the case of the dorsal project forward in
front of the basal stem. G-izzard present; glandular stomach, muscular and folded.
Setigerous processes eighteen pairs, commencing on the second segment (third, Hessle).
Bristles simple, long, tapering and winged. Hooks on slight lateral ridges in the
bristled region (from segment 7; 8, Hessle), and with long curved shafts (rostrate);
-thereafter pectiniform on uncinigerous lamellse, and minute, the outline short and broad
with two or more teeth above the main fang. Anterior nephridia with long and well-
developed tubes, the posterior are small. They occur in the third, sixth and seventh
.segments. Tubicolar in mud or muddy sand.
1; Terebellides Striemi* Sars, 1835. Plate CXX, fig. 3—body; Plate CXXVII,
figs. 5—5 b—bristles and hooks.
Specific Characters. Frilled cephalic plate elevated above the dorsal outline, and
the margins meet in the middle line ventrally to form a spout-shaped channel behind the
mouth. Cephalic plate directed anteriorly and posteriorly instead of dorsally and
ventrally as in Polycirrus and other forms. The posterior, edges of the plate give origin
to the tentacles, which are of a pale flesh colour and often spatulate. Body 60 mm. long,
enlarged in front and gently tapered to the tail, which is by no means slender. Segments
fifty to fifty-six, of which eighteen are anterior. Ventral surface with bold glandular belts
(Hessle). Third, fourth and fifth segments have ventrally free anterior borders. The
1 Coalesced (Grube). •