I t extends to various parts of the Arctic Sea, to the Gulf of St. Lawrence (where it
is common), and to the shores of America (Verrill).
Head (Plate XXVIII, fig. 10) about as long as broad, with two acute peaks in front.
The two posterior eyes are much nearer each other and smaller than the anterior pair—
which are situated within the dorsal margin of the widest part of the head, and therefore
considerably removed from the anterior peaks. These eyes in the Canadian forms are
further forward, more lateral in position, and present in some a lens-like central thickening,
and both they and the posterior pair are larger than in the European forms, which have
eyes of moderate size. The median tentacle is brownish, with a slight swelling below
the very long filiform tip. It has numerous long clavate cilia. The lateral tentacles are
small and subulate with a tapering tip, and have short clavate cilia. The palpi are long
and tapering, furnished with minute and somewhat clavate papillge, which often have
processes at the tip. A few of the papilla occur on the tapering extremity. The
tentacular cirri have very long slender tips and numerous clavate cilia of moderate length,
a few shorter forms occurring on the filiform region distally. These organs are boldly
areolar, and, like the tentacle, are tinted brownish.
Body.—Somewhat broad, tapered a little in front, and more distinctly so posteriorly;
bristled segments thirty-eight. The colour is brownish dorsally, generally arranged in
belts across the segments, which posteriorly show a broader belt in the middle and a
narrow one in front and behind. The Canadian preparations are darker, the tubercle on
the cirrigerous segments being dark olive, so that the tints are striking. As usual, the
pigment is broken up in the terminal segments, and a pale bancL occupies the median
line. The under surface is pale. The segmental elevations are well marked and project
posteriorly as distinct processes, while the papillae are directed nearly straight backward
instead of between the feet. A marked feature ventrally is the prominence of the
spinigerous lobe of the ventral division of the foot.
Proboscis.—The extended proboscis has nine conical papillae dorsally and ventrally.
Scales (Plate XXXIII, fig. 17).—All the Norwegian examples show that the ovoid
or rounded scales have their surface covered with small conical spines; indeed, in the
Arctic examples these are visible under a lens. The spines in the posterior scales (those
alone present) attain larger dimensions externally and anteriorly, and three or four larger
conical processes are found on the posterior border. Cilia, of considerable length in the
latter case, occur on the outer and posterior borders and invade the neighbouring surface.
They are slender and translucent, with clavate tips.
On the other hand, the scales of the Canadian examples were more or less smooth,
soft, somewhat reniform, and furnished with cilia of moderate length on the outer and
posterior borders and on the neighbouring surface. The opacity of the scale, however,
may hide the spines if they are few. At any rate, in the specimen from Barent’s Sea
numerous conical papillae were present. Unfortunately many have no scales, and at best
they are few in the preparations.
Feet.—The first foot bears a strong spine and about three bristles of the dorsal type,
very slightly curved, and with boldly marked spinous rows. The spine forms a powerful
projecting process in large specimens.
The second foot is also marked by the great prominence of the dorsal spine, and has
a series of somewhat strong slightly curved bristles with well-marked spinous rows, which
in profile occupy only about half the bristle, the inferior half being thus smooth and
translucent. Only a minute portion of the tip is bare. Ventrally are a series of slender
bristles, with long spinous regions and capillary extremities.
In the typical foot (Plate XXXI, fig. 2) the dorsal spine is still very prominent, and
the bristles are long, slightly curved, and with a moderately acute tip. The spinous
rows are distinct, and leave only a very short portion of the tip bare (Plate XL, fig. 7).
The ventral are slender, elongate, with long spinous regions and remarkably attenuate
tips, which form long hair-like processes (Plate XL, fig. 8). The foot has a long process
for the spine superiorly. In the terminal segments the character of the bristles alters
little, except as regards size.
In the Canadian examples thecate Infusoria are common on the dorsal bristles,
and, in some, Loxosomse. Infusoria also frequent the British form, and a cluster occurs
in one on the projecting spine of the ventral division of the foot.
The dorsal cirri are long and tapering, with a filiform tip, while the surface has
numerous short clavate cilia. The ventral cirrus is subulate and rather long and
tapering, with numerous short clavate cilia.
In certain respects, e. g. the slenderness of the ventral bristles in comparison with
the dorsal, and in the clearly separated rows of spines, Antinoe approaches Evarne.
Reproduction.—None of the specimens give any light on this process.
Habits.—So far as present knowledge goes, this species would seem to frequent
deep water only.,,
Ehlers (1871), in his account of the Spitzbergen annelids, gives a very interesting
description of two well-marked colour-varieties of this species. The more abundant
form presents the brown coloration which Malmgren states distinguishes the Spitzbergen
from the Baltic form. In the other the scales are bordered with greenish-grey
on the inner and posterior margins, with a darker spot at their junction, the ventral
surface and feet being colourless. The. dorsal surface of each segment is banded with
greyish-green, the pigment being variously developed in different examples. This
variety attains even larger dimensions than the first, viz. 46 mm. in length and
24 mm. in breadth, as against 35 mm. and 17 mm. He contrasts these two varieties
with that now living in the Baltic, which is smaller, possesses a greenish dorsal
coloration, and scales with brownish margins,—that is, it has an intermediate position.
He is of opinion that it has retained, since the glacial period (when the Baltic was
united with the Arctic Sea), the original coloration, from which the two races in the
Spitzbergen Sea have been developed by differentiation.
Ehlers found a Nucula 8 mm. by 6 mm., and 4 mm. in thickness, in the intestine of
one of the largest greyish-green varieties. The same author (1875) describes it from
the ‘ Porcupine ’ Expedition of 1869 at 1215 fathoms, and gives good figures of the
bristles. His specimens had respectively twenty-nine and thirty-five segments.
Hansen found it in the collection made by the Swedish Expedition of 1876.
Marenzeller (1877) includes this form also in the annelids of the Austrian North
Polar Expedition from a depth of 240 metres on mud.
Verrill (1879) enters it in his list from Cape Cod to the St. Lawrence, where
Mr. Whiteaves dredged it in 1873.