with the dorsal margin of the foot. The bristles are somewhat stronger and the spinous
regions shorter. The tips of the upper series are less acute, and those of the stouter
inferior show traces of the expansion. The backward curve of the lower series is
marked. The ventral cirrus reaches only to the tip of the adjoining fleshy part of the
foot.
In the next (fourth) foot a slight elevation internal to the long sheath for the spine
exists, as an indication of the dorsal division. The tips of the ventral bristles are now
shorter and wider.
In the typical foot (Plate XXX, fig. 11) the dorsal division forms a small process
on the upper and anterior border, and is best seen in the elytrophorous feet, since the
enlarged base of the dorsal cirrus in the others obscures it. The inconspicuous tuft
consists of slender translucent bristles with faint serrations, and tapering to a fine point
(Plate XLI, fig. 1). The bristles of the ventral series are comparatively slender and
translucent, while the tips are flattened out in varying degrees. The superior series
(Plate XLI, fig. 2) have elongated spinous regions, and simple, slightly blunt tips ; while
the broader middle series (Plate XLI, fig. 3) have a strong curved hook at the tip, with
a secondary process immediately beneath. The flattened spinous region is marked by
the oblique lines from the rows of spines as in Malmgrenia. Langerhans specially refers
to the changes in the bifid tip of the ventral bristles. The ventral cirrus does not now
reach the tip of the fleshy part of the foot.
Posteriorly the bristles become extremely slender, with a capillary tip. The ventral,
however, retain a trace of the enlargement at the base of the spinous region. The
bristles on the last foot are stout. The ventral cirrus extends almost as far as the tip of
the inferior division of the foot.
Parasites on the bristles are rare.
The dorsal cirri are rather long, slender organs, with ;a filiform tip, and a dark belt
at the slight swelling immediately below. Their surface is smooth. A considerable
nerve passes up the centre of the organ nearly to the tip, giving off branches as it
proceeds.
Habits.—This species is fond of clinging to the under surface of stones in pools near
low--water mark, from the north of Scotland to the Channel Islands, and no marked
difference in size is found on contrasting specimens from the extremes. In Bressay
Sound i f is very abundant in old bivalve shells, in crevices in the “ roots” of the
tangles, and on the surfaces of the valves of the “ horse ’’-mussels bound together by
the foregoing “ roots.” Sir J. Dalyell many years previously procured it from this
region—under shells. He gives an interesting account of the rapacity of one in confinement
which devoured its fellow, the teeth of the proboscis audibly striking the
glass as it darted it out to. conclude its meal. In various Polynoidae this tapping on
the glass occurs occasionally in confinement. Fishes seem to find it out readily in
deep water, for large examples are frequent at St. Andrews in the stomach of the cod
and haddock.
It is active and irritable, and frequently ruptures its body if held by the middle, or
when put in spirit. Sir J. Dalyell found it timid and nocturnal, yet watchful for prey.
Reproduction.—Ripe males occur at St. Andrews towards the end of November. A
large female, again, was laden with fairly advanced ova in July in Herm, so that the
period of deposition could not be distant, probably in autumn. They were somewhat
less advanced in a large female during the same month in Shetland, no free ova occurring
in either case. In August the condition of the ova was very similar to the last (e. g. in
one sent from Arran by Dr. Howden). Sir J. Dalyell, again, found that in the middle of
July a large specimen produced in confinement about 10,000 eggs, the mass having a
reddish hue as it lay on the bottom of the vessel. De St.-Joseph found ripe specimens
with the ova and sperms within a membrane, as shown by Claparède in Hermadion
fragile, but he omits to mention the date.
De Quatrefages adds nothing new to the account of the species. Grube found that
this author’s Polynoë foliosa in the museum at Paris agreed with the present species, as
Malmgren had hinted.
Ehlers gives a somewhat detailed description of the small specimen (13-5 mm.) from
the ‘ Porcupine.’
Genus XX.—Polynoe, Savigny, 1820.
Head elongated antero-posteriorly, with a somewhat indistinct peak on each side,
beneath which is the lateral tentacle. Anterior and posterior eyes widely separated.
Palpi with dense rows of clavate papillae. Body linear-elongate, with many segments
(over 100). Segmental papillae long. Scales fifteen pairs, with a broad belt of papillae
on the surface anteriorly. Dorsal division of the foot minute, with small spinous bristles
truncated at the tip. Ventral division has a single strong hastate bristle superiorly, and,
below, strong bifid bristles with short spinous regions.
The median area for the nerve-cords is comparatively wide, the oblique muscles
having a broad attachment to its exterior border. A firm membrane bounds the area
internally, and a symmetrical longitudinal muscle runs above it on each side of the
median line.
Commensalistic.
Polynoe scolopendrina, Savigny, 1820. Plate XXV, fig. 7*.
Specific Characters.—Head pinkish, with the long diameter antero-posterior; a
somewhat indistinct peak on each side. A pair of distinct eyes in front of the nuchal
collar, and a larger pair with lenses, scarcely visible from the dorsum, near the anterior
part of the peak, and directed forward and slightly outward. Median tentacle larger
than the palpi in spirit, with a slight enlargement below the filiform tip, and densely
clothed with short clavate cilia having truncated tips. Lateral tentacles of moderate
length. Palpi have dense rows of minute clavate papillae. Body linear-elongate, 2 to 5
inches long, bristled segments from 80 to over 100, reddish brown, or brown on the
dorsum, the pigment being arranged in various touches and bars. The posterior ventral
region has also brown bars and touches, especially on the segmental eminences. The