of the axis, and the rest is flattened out to form the terminal blade, which tapers
somewhat suddenly from the broad base to a fine hair-like extremity, the edge opposite
the process having a thickened rim, whilst the other is minutely serrated. Malmgren’s
artist has not very accurately interpreted the basal part.1 The second series of
translucent bristles is shorter and often shows a slight curvature of the shaft, the
process or rib at the tip of which is considerably longer than in the former series,
the serrated blade passing off with a broad basal web to the hair-like tip. The rib
or process in both longer and shorter would appear to stiffen the terminal web.
The posterior bristles are brittle, and few remain after capture. They consist of
long, slender, translucent shafts bifid at the tip—that is to say, the web at the tip is
stiffened by two spur-like thickenings, which support the serrated web between them.
They show no long, tapering extremity as in front.
From first to last the setigerous processes are closely associated with the ridges
for the hooks, and indeed form part of them, finishing as it were the dorsal end by
a pointed process. Anteriorly the process is nearly transverse, but by-and-by it slopes
backward, especially posteriorly, where the bristles pass from its posterior and upper
angle. From the second branchia backward eight papillae occur above the rows
of hooks.
The hooks (Plate CXXVI, fig. 8 b) commence on the ridge passing from the first
bristle-tuft ventrally toward the shields (fifth segment, De St. Joseph), and the succeeding
ridges gradually increase in prominence until they are conspicuous latero-ventrally.
The first row is single, but at the eleventh a double row occurs, and this continues
a considerable distance, but on the small posterior ridges “only a single row is- found.
The typical hook has a large main fang and three teeth above it, the posterior margin
is nearly straight, its distal end curving to the crown, and its basal bending outward
to form a process of the base. The latter is of moderate length, convex inferiorly,
and with a sinuosity in front. The curve beneath the chief fang is abrupt and ends
in a prominent process, and below it a curve goes to the anterior prow. Although
only three teeth are observed above the great fang in profile, numerous teeth appear
when the crown is viewed from above. In the first row of hooks the bases are altered,
the anterior prow being prolonged, and the sinus above the base posteriorly being more
pronounced than [in the typical hook. Anteriorly the outer edge of the groove for the
hooks is free, so that it sometimes resembles a papilla.
The body, the tentacles and the branchiae occasionally swarm with Rhabdostyla
sertulariwn, Sav. Kent (De St. Joseph).
Reproduction.-—Dalyell (1853) describes the ova as red and embedded'»in albuminous
matter. He does not give the date. De St. Joseph found an example with ripe eggs in
August.
Habits.—Like Marphysa sanguinea and Girratulus cirrakis, Leprea has a habit of
forming a siphonal bend in its tunnel in the fissure of the rock so that both head and tail
can be thrust out at the free edge. It is rare, according to De St. Joseph, on shores
bordered by granite at Dinard.
This species was first described and figured by H. Martin Kahler (1754) as a polyp
1 ‘Annul, Polych./ Tab. xii, fig. 69b,
which perforated stones, though Linnaeus subsequently placed it under the Terebellids.
Its habit of occurring in fissures of rocks with its siphonal tunnel had misled Kahler.
Dalyell’s (1853) small examples constructed cylindrical sheaths of sandy or muddy
particles and insufficient to cover the body. The sheath was frequently abandoned.
They also, he narrates, produce a “ real cobweb” of mucous threads with which they
cover themselves and support the spawn.
The laxity of De Quatrefages’ arrangement (1865) and the subsequent confusion
is illustrated in this species, which was included under the genus Idalia, and afterwards
described as a new form under the title Heterophyseiia Bosci.
Malmgren’s account (1865) was probably drawn from specimens in the British
Museum, and his description refers to Leprea lapidaria, which had been confounded with
Dalyell’s L. textrix in the collection.
Marenzeller (1884) gave a careful digest of the literature of this species, and
corrected the synonymy up to date.
Gravier1 (1906) thinks that this species perhaps secretes an acid, which enables it to
attack the calcareous masses amongst which it lives. It is nowhere more abundant than
in the gneiss of Guernsey in fissures and crevices of the rocks, where the secretion of an
acid would not be effective, so that the secretion is not always of service in this
respect.
De St. Joseph2 (1906) found a Rotifer, Discopus synaptse, on the skin of this form
at St. Jean-de-Luz.
In the British Museum, preparation 66 . 8 .2 0 .1 4 , attached to the shell of a Pinna
from Polperro, and labelled Terebella constrictor, is Leprea textrix.
Germs CLII.—T h e l e p u s , Leuclcart, 1 8 4 9 .
iMmara, Stimpson, 1855; Neottis, Malmgren, 1865; Phenacia, Heterophyseiia and
Heterophenacia, De Quatrefages, 1865; Thelepodopsis, Sars, 1871; Venusia, Johnston,
1855; Heteroterebella, Panceri.
Cephalic lobe with a well-marked dorsal collar, the external rim passing to the
ventral surface, and joining the lower edge of the supra-oral arch, the intervening space
being occupied by the inner tongue-shaped process and the fillet of the post-oral segment.
Anterior surface of cephalic plate occupied by the tentacles. Numerous ocular specks.
Body typical, though the ventral scutes are often indistinct. The dorsal surface
frequently has rounded glandular furrows. Branchiae a filiform transverse series (two or
thi ’ee on each side, rarely one) on the second and third segments. Setigerous processes
commence on the third segment, and extend to the posterior end. The avicular hooks
begin on the fifth segment and also continue to the penultimate segment in a single row,
and in some the row ends in a loop or circle. Nephridia increase in size from front to rear.
Tube long and membranous, with fragments of shells, zoophytes, and other foreign
structures externally.
Grube (1 8 7 8 ) adopts the title Phenacia of De Quatrefages for this group.
1 1 Nouv. Archiv. Mus. Paris/ 4e ser., t.. viii, p. 210.
2 ‘ Ann. Sc. nat./ 9° ser., t. iii, p. 175.