1. Polycirrus medusa, Grube, 1855. Plate CXIIIa, fig. 8—body; Plate CXXVI,figs. 9—
9 b—bristles and hooks.
Specific Characters.—-Cephalic lobe without dorsal collar, the plate passing forward
as a hollow hoof, the sides of the vertical slit leading to the mouth spreading out as two
rounded lamellae, which externally and dorsally sharply fold and end in a prominent
fillet on each side. Tentacles numerous, ciliated, the smaller clustering on the sides of the
vertical slit. Body 1 to 4 inches long, enlarged in front and tapering to a moderately
slender tail with a terminal anus. Segments from fifty to eighty-eight. First ventral
scute large and single, narrow in front, broad and rounded posteriorly, followed by a narrow
belt also, single, and then a series (six to eight) split by a median groove into pairs in each
segment. Thirteen pairs of bristle-tufts (eleven to fourteen, Grube), each setigerous
process being prominent and dorsally bifid, with a longer and a shorter limb. Lamellas
for the hooks commence behind the last bristle-tuft (sixteenth segment, Hessle), and continue
to the end. The hooks have the basal outline convex, and two teeth above the
main fang. No visible striae at base. Nephridia from the third to the eighth segment.
Colour golden or pale yellow, the same tint appearing on the tentacles. Some have the
anterior region of a deep orange, the posterior half being paler. Bristles in two series,
long, slender, with shafts slightly narrowed above the origin, tapered and curved distally.
No wings. The shorter series similar in structure, but more attenuate. The first tuft is
on the third segment (Hessle). Uncinigerous processes commence as slight ridges; by-
and-by become prominent bosses or papillae. Hooks in a single row with elongate bases,
which are convex both in front (below the main fang) and behind the middle interiorly,
with a single tooth above the main fang as a rule, though a second is seen occasionally
posteriorly. Tube, a tunnel in mud or of soft sand.
1855.
1861.
1865.
1867.
1871.
1874.
1875.
1879.
1881.
1882.
1883.
1885.
Synonyms.
Polycirrus medusa, Grube. Arch, fur Naturges., p. 120.
. „ idem. Ausflug. Trieste u. Quarnero, p. 78.
Ereutho smitti, Malmgren. Nord. Hafs.-Annul., p. 391, Tab. xxiii, fig. 63.
Apneumea medusa, De Quatrefages: Annel., t. ii, p. 383.
Ereutho smitti, Malmgren. Annul. Polych., p. 111.
„ „ Sars. Vidensk.-Selsk. Forhandl,, p. 10 (sep. abdr.).
a a McIntosh. Trans. Roy. Soc. Edin., vol. xXv, p. 424, pi. xv, fig. 17.
- a a' Sars. Vidensk.-Selsk. Forhandl., p. 253.
,» Ehlers. Ann. Nat. Hist., ser. 4, vol. viii, p. 57.
. „ , ‘ „ \ McIntosh. Ibid., ser. 4, vol. xiv, p. 205.
„ „ idem. Invert, and Fishes St. Andrews, p. 130.
Polycirrus medusae, Panceri. Atti Soc. Ital. Sc. Nat., vol. xviii, p. 231.
Ereutho smitti, Tauber. Annul. Danica, p. 134.
’ a Theel. Kgl. sv. Vet.-Akad. Handl., Bd. xvi, p. 64.
ii a Horst. Niederl. Arch. Zool., Suppl., Bd. i.
a a Ar. Hansen. Norske Nord. Expect, p. 22.
Leucariste smitti, Levinsen. Vid. Meddel. Forh., p. 173.
Polycvrrus medma, Oarus. Fauna Medit., i, p. 267.
1886. Ereutho smitti, Marenzeller. Polarfarsch., p. 15.
1887. „ „ Webster. U.S. Com. F. & F., p. 749.
1888. „ „ Cunningham and Ramage. Trans. Roy. Soc. Edin., vol. xxxiii, p. 666.
1889. Polycimis smitti, E. Meyer. Arch. f. Nat., lv, p. 133.
,., Leucariste ,, Levinsen. “Hauchs” Annel, p. 351.
1894. ,, „ Bidenkap. Christ. Vet.-Akad. Forhandl., p. 125.
1897. a . a Michaelsen. Polych. deutsch. Meere, p .176.
,, ' „ „ Appellöf. Bergens Mus. Aarb., No. 13, p. 12.
1899. Polycirrus medusa, Ssolowiew. Annuaire Mus. Acad. Imp. St. Pétersbourg, t. iv, p. 188, Tab. x,
figs. 1, ;2.
1912. Ereutho smitti, Wollebæk. Skrift. Vid.-selsk. Krist., pll xx, figs. 1—4.
, ,, Meyer, A. H. Inaug. Dissert. Kiel, p. 54.
1913. Polycirrus medusa, Augener. Zool. Anz., Bd. xli, p. 271.
1914. „ Smitti, Southern. Proc. Roy. Irish Acad., vol. xxxi, No. 47, p. 127.
,, Leucariste smitti, Ditlevsen. Polych. Grönland., Heft 23, Abt. 3, p. 726.
„ Polycirrus aurantiacus, Fauvel. Gampag. Scient. Monaco, xlvi, p. 309.
1915. Ereutho Smitti, McIntosh* Ann. Nat. Hist., ser. 8, vol. xv, p. 36.
• „ Polycirrus aurantiacus, idem. Ibid., ser. 8, vol. xv, p. 33.
„ „ Smitti, Southern. Irish Sc. Invest., No. 3, p. 47.
1917. „ medusa, Hessle. Zool. Bidr. Uppsala, p. 220.
Habitat.—Not uncommon near low water-mark at the East Rocks under stones and
between layers of rock, St. Andrews (E. & R. M.); on a coralline dredged in the Minch;
amongst tangle-roots in 6—8 fathoms, Bressay Sound, Shetland (W. C. M.); in similar
places in the Forth (Cunningham and Ramage); Blacksod Bay, in gravel, and in sand
in Galway Bay, between tide-marks (Southern)* Elsewhere it has been found at
Spitzbergen and Greenland (Malmgren, etc.); 300 fathoms off Norway (Sars); Franz
Joseph Land (Augener); White Sea (Ssolowiew); Bergen (Wollebmk); Mediterranean
(Grube). Cosmopolitan.
The cephalic region is characterised by the absence of a distinct dorsal rim, the smooth
spout-like supra-oral fillet passing forward in the median line, and each side, bending
downward, forms a broad rounded flap at the ventral edge, the arrangement being
symmetrical. The external margin curves outward and upward, almost to the dorsal
edge, then doubles sharply backward as a fillet and ceases. When the neck is viewed
from the dorsum these fillets are conspicuous on each side. From the entire surface of
this cephalic plate arise the dense mass of bright yellow tentacles which form inextricable
coils both in life and in spirit, whilst from the edges of the lateral flaps are many small
filaments. The tentacles are mobile, grooved organs capable of endless changes, now
flattened and again rounded, coiled and twisted in various ways, or again corrugated and
wrinkled. The body is pulled along by these organs, which move like linear planarians
over the glass. The small tentacles at the margin of the cephalic lobes keep constantly
coiling, and the animal soon covers itself in a glass vessel with debris of various kinds,
and through the meshes of its cover the long delicate tentacles everywhere emerge.
These tentacles in life show a pale central streak, their sides are dotted with minute
yellow granules, and the ridges are ciliated. Their muscular fibres form meshes, and
though no circular coat is apparent the oblique and connecting fibres would to a large