Habitat.—Several examples were dredged in 6 to 10 fathoms, amongst tangle-roots,
in Bressay Sound, Shetland, classic ground to marine zoologists since the days of Edward
Forbes. A form apparently identical occurs in the British Museum, from chinks in the
rocks, Polperro, Cornwall. The same form is found in the Adriatic.
Length about seven-tenths of an inch.
The head (Plate XXVIII, fig. 3) is elongated from before backward, and since the
large anterior pair of eyes are carried outward, almost at the tips of the pea.ks, beneath
which they are placed, and are visible from the dorsum, the condition is diagnostic.
They are, moreover, wider apart than the posterior pair, and look forward and outward.
The smaller posterior pair are dorsal, situated near each other, and almost touch the
nuchal collar (in spirit). The two pairs of eyes are thus separated by a long anteroposterior
interval. The median tentacle has a broad base, a brownish Column, a pale tip
with little or no enlargement beneath, and well-marked clavate cilia. The lateral tentacles
are inferior in position, small, subulate, and with similar clavate cilia. The
tentacular cirri are also brownish, furnished with numerous clavate cilia, and slightly
enlarged below the filiform tip. The palpi are brownish, with rows of small blunt papillae,
which are sometimes bifid at the tip.
The body, which consists of thirty-seven segments, is comparatively short and of
more uniform diameter than usual, being only a little narrowed anteriorly, and somewhat
more posteriorly. Transverse markings occur on the dorsum between the scale-pedicles
and their homologues. No pigment remained on the dorsum in the preparations, though
it is probable traces of such were present during life. On the ventral surface traces of
brownish pigment occur at the sides of the prominent fold in front of the jnouth. The
lateral prominences at the bases of the feet are well marked, but the segmental processes
are minute.
Scales (Plate XXXIII, fig. 4), fifteen pairs. The first are small, nearly circular, and
their light brownish colour contrasts strongly with the succeeding. The surface is
studded with short blunt spines, which are especially distinct at the outer border, where
there are also a few short clavate cilia. The rest of the margin,is smooth. The second
pair are reniform, the exposed parts being almost uniformly black, with a silky sheen and
a smooth margin, except at the outer border, where five or six very short clavate cilia
occur at intervals. The short blunt spines are distributed over the posterior two thirds
of the surface. The third scales are also blackish with the same metallic sheen, but
have a few minute pale points besides the microscopic blunt spines. The pale specks
increase in size in the succeeding scales, and the pigment becomes paler, the posterior
pair, indeed, being mottled like granite. The general shape of the posterior scales is
irregularly rounded or ovoid, with the scar for attachment towards the anterior and
outer border. The penultimate and last pairs are much elongated from before backwards.
The number of the minute blunt spines diminishes posteriorly, so that they are
chiefly confined to the outer border, where an occasional short clavate cilium is observed.
The definite pale areas are due to the absence of pigment in the areolse of the epiderm
(hypoderm), while in the dark parts each areola is deeply pigmented. If the P. spinifera
of Ehlers is the same form the scales had a greyish-violet sheen.
Feet.—The first foot shows dorsal bristles, which are little altered from the typical
form.
The second foot has dorsally a series of short broad bristles, the tips especially
being characteristic. Ventrally the shafts of the bristles of the region are stout, and
the spinous tips well marked. The superior bristles have very short smooth tips, which
are bifid. There is thus less change than usual in the foot.
In the typical foot the superior branch bears a short cirrus, the tip of which (in
spirit) reaches the extremity of the bristles. I t is almost cylindrical, except near the tip,
where a gradual diminution occurs. The surface has rather, numerous stout clavate cilia,
which are best developed on and near the slight enlargement below the filiform tip. The
•ventral cirrus has an enlarged base, reaches a little further than the insertion of the
inferior ventral bristles, and has a few stout clavate cilia.
The dorsal branch of the foot has comparatively short and not very stout bristles,
slightly curved, and finely serrated. The smooth tips are peculiar, being fashioned like
a blunt Esquimaux harpoon or paper-scraper, as represented in one of the larger
examples (Plate XXXVIII, fig. 17). The spinous rows at the distal part project
characteristically at a greater angle than usual, but are generally obscured by dense
granular parasitic growths and mud.
The ventral bristles have comparatively stout shafts and short spinous regions.
The smooth tip is also short. Every bristle is boldly bifid. The superior series (with
longer spinous rows) have a very short smooth region (Plate XXXVIII, fig. 18), the
longer terminal part being only diminished on its dorsal edge—not hooked, while
the secondary process is stout and goes straight to a point, thus differing from the
attenuated divisions of Parmenis ljungmani. The smooth tips of the middle and inferior
bristles (Plate XXXVIII, fig. 19) are somewhat longer and have a slight hook, but the
secondary process is straight. The spinous . regions in these are proportionally
short.
Reproduction.—The specimens procured in July had the ova well advanced, so that
their spawning period would seem to be in autumn at latest. I t is interesting that
the examples of Ehlers and De Saint-Joseph also carried eggs. The latter found a
specimen of 7 mm. in the same condition.
This species presents considerable differences from Parmenis ljungmani, Malmgren.
The body is larger and broader, the segments thirty-seven instead of thirty-five or
thirty-six '; the head is more elongated, and the arrangement of the eyes different. Thus,
for instance, the smaller anterior eyes in the northern form are situated at an incurved
region of the head just in front of the middle. The dorsal bristles are thicker than the
ventral, and have the peculiar tips indicated, whereas in P. ljungmani the tips are simply
tapered. The ventral bristles have short spinous regions in both, but in the Zetlandic
form the tip is less hooked, and the secondary process is short, stout, and straight.
There are points of similarity between the forms, but there is no warrant for 'uniting
them.
The Polynoe spinifera of Ehlers approaches this species very nearly, and he probably
overlooked the papillaa on the palpi. I t is possible the small size of his example (7 mm.)
may have been the cause of certain variations. The figures and remarks of Langer