of further examination, though but a single pair of branchiae occurs in each with
sixteen and fifteen bristle-tufts respectively in the first and second. Whatever may be
the result in regard to these northern forms, the British species of Nicolea now define
themselves more clearly, notwithstanding all the variations in branchias, bristles and
hooks.
Two varieties of the species are found, viz., those from deep water, with the anterior
pair of large branchiae on long stalks, and the littoral forms with short branchiae. Some
might be inclined to make two species, but the general structure and especially the
hooks of the two forms so closely agree that for the present they may be united.
In this connection the figures of Malmgren are not diagnostic. It is interesting that
all the smaller forms (his N. zostericola) kindly sent by Dr. Allen from Plymouth had
small branchiae and fifteen pairs of bristles, whilst all the larger (his N. venustula) had
seventeen pairs of bristles. The hooks of the two were identical, and it has to be
remembered that whilst the anterior hooks have but a single tooth above the main fang
in lateral view, or at most indistinct traces of a third, the posterior hooks have two teeth
above the main fang.
So far as present experience goes it seems to be unnecessary to separate
Scione lobata, Malmgren, from the foregoing, even though examples are found
with only a single pair of branchiae. At least no basis for this view has been
satisfactory.
Montagu’s account (1818) is brief, and there is nothing distinctive in the figure,
to which the artist has given an eye on each side of the anterior region. He dredged
it on the south coast of Devon at Torcross. It had seventeen pairs of bristles, an
orange-red body, thickly and minutely marked with red spots.
Dalyell1 (1858) gives a description and figure of Terebdla metadata, a form about
1^ inches long, and the “ lower” extremity of which ends in points. A single pair
of sparsely divided branchige only occur, the tentacles have spots of brown, and he
mentions “ a row of short, obtuse teeth” on each (probably referring to crenations).
It is mottled, patched, or speckled with various colours, wherein brown, green and
yellow predominate. Its tube is composed of grains of sand attached to corallines. This
may refer to another species of Nicolea.
The Polymnia viridis of Malm2 (1874) approaches Nicolea in general appearance and
in the branchiae.
A critical survey of the genus and species is given by von Marenzeller (1884), who
points out that the number of the branchiae and the number of the bristle-tufts vary,
the former from two to three and the latter from fifteen to seventeen. The southern
examples would appear to form a distinct variety, in which the three branchiae and
seventeen pairs of bristle-bundles are common.
Cunningham and Ramage8 (1888) describe a Scione maculata (Terebella macidata,
Johnston) with sixteen pairs of bristle-tufts anteriorly and a lateral semicircular lobe on
each side from the third segment. The anus has six to seven conical papillae. They
1 ‘Power’s Creat.,’ vol. ii, p. 203, pi. xxviii, figs. 10—19.
8 ‘ Göteborg Fauna,’ p. 97.
8 ‘Trans. Roy. Soc. Edin.,’ vol. xxxiii, p. 665, pi. xliv, fig. 27.
consider it to be the same form as Dalyell’s T. maculata. The bristles are winged, and
the hook figured resembles that of a Nicolea.
Marenzeller in a later paper (1890) included Nicolea arctica, Malmgren, and
N. zostericola, Grube, under this species, and he found occasionally only fifteen bristle-
bundles in some typical representatives.
De St. Joseph (1894) gives the colour as brick-red, and he notes that Michaelsen
found it also at Kiel. The oesophagus extends to the ninth setigerous segment, the
glandular stomach to the sixteenth, the “ chitinous ” stomach to the first abdominal
segment, and then the intestine ends at the tip of the body. Gregarines occurred in the
intestine, and two encysted Distomes similar to those in Nerine longirostris were present
in the coelom. This author subsequently (1906) mentions the occurrence of Ulvinia
ellvptica, Ming, (which Siedlecki found in Terebella nebidosa),1 also of Selenidium costatum.
Both occur in P. nebidosa.
Ssolowiew (1899) includes, after Levinsen and Marenzeller, N. zostericola and
N. arctica as synonyms of this species.
Leschke 2 (1902) alludes to the larval form as first mentioned at Kiel by Willemoes-
Suhm. The species is ripe from April to June. The earliest larvae are fpund on the
sea-grass, and have three bristled segments in front and three naked posteriorly. The
colour is ochreous. Rudiments of the tentacles appear, and bristles on all the segments,
and it forms a mucous tube. The development is similar to that of Terebella nebnlosa as
described by Milne Edwards.
Southern’s (1914) examples from Clare Island all had seventeen pairs of bristles.
Dr. Allen and Mr. Crawshay, from their observations at Plymouth, consider Nicolea
venustula, Mont., distinct from N. zostericola, CErst. and Grube, and the former kindly sent
the type-specimens for examination. In glancing at them it is apparent that the sizes of
the two forms differ, but whether this is due to race or . to age is unknown, both being
mature. The first pair of branchiae in N. venustula form a much denser arbuscle than in
N. zostericola, but the branchiae of the latter vary amongst themselves and the differences
may be due to age. N. zostericola has fifteen pairs of bristles as a rule, N. venustula has
seventeen pairs, yet Prof. Fauvel has found the latter with only fifteen pairs. In both
the males have the cirrus over the third and fourth bristle-tufts, and in these examples the
cirri were more conspicuous in N. zostericola, but this is a variable character. There is
nothing else distinctive in external appearance. Both have bristles of the same structure,
N. zost&t'icola, the smaller form, having paler shafts and tips, but precisely the same slight
bend and the same narrow wings on the finely tapered extremities, which seem to be of
similar proportions in each. The hooks of N. zostericola are also alternately arranged in
the rows, and each has a dorsal outline nearly straight till it reaches the projection at the
base, this projection or heel being more distinct in the Norwegian forms, the outline of
the latter in the normal position sloping downward and forward to a smoothly rounded
prow, whilst the anterior outline has a process for a ligament about its middle, the
concave curve on each side of this being nearly symmetrical, viz., upwards to the main
fang and downward to the prow. Most of the hooks present only a single tooth in
1 ‘ Ann. Instit. Pasteur,’ July, 1903, p. 430, pi. viii, figs. 1 and 2.
8 ‘ Wiss. Meeresuntersucli.,’ Bd. v, p. 127.