extent supplant them. From the nature of the parts no prominent ventral lip is present,
but the narrow part of the first glandular ventral scute glides under the ventral flaps of
the cephalic plate and runs into the smooth surface, which trends as a shallow groove
forward to the mouth.
The body reaches 2 to 4 inches in length, is more or less dilated anteriorly,
sometimes being largely distended, and it tapers posteriorly to the tail, which in the
preparations is by no means slender, though in life it is often much more attenuate.
It is rounded dorsally, grooved ventrally, and has numerous segments, fifty to eighty-eight
or more. Posteriorly it terminates in a crenate anus, the central papilla ventrally being
the most prominent. Occasionally the anus is carried outward on a small process or
appendix, but such may be due to regeneration. Anteriorly are thirteen pairs of
setigerous processes, and behind these about seventy or more uncinigerous processes
• which occupy the ventro-lateral region.
The muscular fibres of the intestine are curiously reticulated, spaces being left
between the fibres, and apparently there are no evident circular fibres, though the oblique
and connecting fibres would suffice for constriction.
The segment behind the mouth has a single large granular ventral scute, narrow
in front and broad and rounded posteriorly. Then a narrow belt follows, its lateral
regions expanding to include the second setigerous processes. Thereafter a median band
with a central line passes longitudinally backward, cutting the scutes into pairs in each
segment, and of these seven or eight are distinct, each marked by transverse lines. The
segments of the posterior region have a deep furrow in the preparations dividing them
into two, and each of these is again subdivided into three narrow rings.
Viewed from the dorsum each setigerous process is dorsally bifid—a feature better
marked in the smaller than in the larger examples, and the bristles issue between the
limbs. The first setigerous process has a considerably longer anterior cirrus than those
which follow, the posterior process being smaller. In the middle, of the body the
anterior process is shorter and thicker, and the posterior process is more distinct, whilst
the last setigerous process in some has a rounded boss on the tip of the thick, short,
anterior process, and the posterior is at a greater distance from it and smaller
than in the middle of the series. From this bifid region the tip is curved downward
and inward.
The bristles (Plate CXXVI, figs. 9 and 9 a) are in two groups, a longer and a shorter
series. The former are pale golden slender bristles with shafts more attenuate than their
pale bases, and which taper distally to the curved, almost wingless tip. In the shorter
series only the curved tips, which are more slender than the foregoing, project beyond the
surface. The margin from which the bristles issue slopes inward as it passes ventrally,
and the fascicle has a twist as in Streblosoma.
The first uncinigerous process occurs as a slightly elevated ridge at the posterior
part of the segment following the last bristle-bundle, and the succeeding processes
gradually increase in prominence until they form bosses or papillm like the “ feet ” of
caterpillars along the ventro-lateral region of the body to the tail, the terminal processes
being small and closely arranged. The single row of hooks lies on the anterior face of the
tip. The anterior hooks (Plate CXXVI, fig. 9 b) have a base considerably longer than
shown in Malmgren’s figure, the anterior outline below the main fang having a slight
convexity about its middle, whilst at its junction with the posterior outline a distinct
shoulder occurs. The main fang is large and acute, • and the tooth above it is of
considerable size, though not so large as in Malmgren’s figure. The inferior outline
of the base is slightly convex behind the middle, but generally shows an inflection
toward the prow. The hooks retain the main features just mentioned posteriorly,
though the base is somewhat shorter and a trace of another tooth occurs in some on the
crown.
There are six pairs of nephridia.
Habits.—This species is not phosphorescent at St. Andrews.
So far as the description goes this form does not appear to differ from De Quatrefages’
Apnehmea pellucida from Br^hat. The identification of this widely distributed form by
Ssolowiew with the PoVycirrus medusa of Grube cleared up much ambiguity. It is
possible that the Ereutho antarctica of Willey (“Southern Cross,” 1902), maybe a variety.
2. Polycirrus aurantiacus, Grube, 1860, char, emend. Plate CXX, fig. 4—ventral aspect
of a portion of the body ; Plate CXXVII, figs. 1—1 b—bristles and hooks.
Specific Characters.—Cephalic lobe with a slight dorsal collar, and when opened
forming a frilled margin to the funnel-shaped oral region; but when folded ventrally
it has two lateral flaps with a median fissure as in P. medusa. From the surface of this
cephalic plate a dense series of grooved tentacles springs. Body of the typical Terebellid
shape, sometimes enlarged dorsally in the region of the anterior scutes or immediately
behind them. Length 3—4 inches, and with eighty-four to a hundred segments. Of a
dull or pale yellow colour, the intestine appearing through the skin as an orange or dull
reddish tube; the median tongue-shaped ventral scute is followed by seven to eight pairs
closely arranged, then smaller scutes (about twenty) on the longer segments behind.
Setigerous processes begin on the second segment and continue to the number of
thirty-five to sixty. Uncinigerous processes commence on the ninth bristled segment
and continue to the end. Anterior hooks differ but slightly from the posterior. Anus
terminal with a crenate margin, and often a prominent ventral papilla, or occasionally
a less distinct dorsal papilla. Setigerous processes bifid dorsally, the posterior being
the longer division. The margin curves inward ventrally. Bristles in two series, long
and short, the former translucent, tapering from the base, with finely attenuate and
curved tips devoid of wings, and others with just a trace of wings; the shorter bare
capillary forms much more slender, their tips only projecting beyond the surface. The
uncinigerous processes which bear the hooks in a single row on the - anterior face of the
tip are less prominent than in P. medusa, and continue to the end. Hooks with a
long base, a slightly upturned prow, a slight process on the anterior outline below the
main fang, a marked indentation above the posterior basal process, and a single tooth
above the chief fang. They commence on the sixth or seventh segment. Segmental
organs three pairs in one, two and three armed segments after the sixth (Lo Bianco).
Tube composed of sand.