Length 16 mm., but the specimen had the posterior extremity regenerated, and
therefore was probably considerably longer.
The head (Plate XXVII, fig. 10) is more elongate than in L. floccosa, and the
peaks in front terminate bluntly. The posterior pair of eyes are of moderate size, and
lie just in front of the collar; the anterior pair are somewhat further forward than in
the species mentioned, are larger than the posterior pair, have a lens-like centre, and
are more or less lateral in position. The median tentacle is absent. The lateral tentacles
are short and subulate, being lateral in position, and only slightly beneath the bases of
the former. They have a series of cilia with clavate tips. The tentacular, like the dorsal
cirri, are rather slender, with a filiform tip and a series of clavate papilla, which do not
conimence. till the basal third of the process is reached, and extend within a short
distance of the filiform tip. They are in moderate number, and diminish at each end of
the series. The palpi are pale brown, and have rows of minute papillae with expanded
nodular tips. Two of these rows are dorsal.
The body is somewhat narrowed anteriorly, and posteriorly appears to have been
recently regenerated after the twenty-fourth foot. The only colour exists in the dorsal
fold of the mouth, which is brownish.
Scales (Plate XXXII, fig. 7).—The first pair of scales are rounded, and under a lens
are minutely speckled as if variolated. This condition, however, is due to hypodermic
structure, and does not affect the surface. The latter has a series of minute spines,
which densely cover the outer and posterior part of the scale. Even, in these scales a
distinct fold occurs anteriorly, but no cilia on the edge.—The other scales present
are rather large, ovate-reniform in outline, and have a distinct fold from the scar of
attachment to the hilus at the anterior border. They are faintly brownish in hue (in
spirit), and on a dark surface—under a lens—are speckled throughout the posterior half
with pale specks which simulate pustules. The outer border has a well-marked series of
long cilia, which are not dilated at the tip. The smoothness of the edge of the scale,
•with this exception, is noteworthy.
Feet.—The second foot shows rather short and straight dorsal bristles, with distinct
spinous rows as in Lagisca floccosa, var., from the ‘ Porcupine,’ 1 with a very short
smooth portion of a bluntly conical shape at the tip. The ventral bristles are slender,
with elongate spinous regions and attenuate tips.
In the third foot the ventral bristles are stronger, and the bifid condition distinct in
many—the secondary process passing nearly straight towards the tip.
In the typical foot the dorsal bristles (Plate XXXVIII, fig. 7) are of moderate
length, with well-marked spinous rows and a very short smooth tip. They are nearly
straight, with the exception of a few at the inner border of the tuft. Loxosomx and algoid
growths are common on these bristles. The ventral division has a dense group of pale
bristles with elongated shafts, and, though the upper forms (Plate XXXVIII, fig. 8)
have long tips, on the whole with rather short spinous regions, as shown in one from
the middle of the foot (Plate XXXVIII, fig. 9). These bristles have very distinct spinous
rows, a short bare tip with a strongly curved hook at the end, and in the majority a
secondary process which is directed nearly straight distally, so that they differ quite from
1 Vide p. 302.
those of Lagisca floccosa, which have longer spinous regions and a different curve at the
tip. The ventral cirrus has well-marked clavate cilia. The segmental papilla is minute.
In the presence of the pale specks on the scales it resembles the rare Polynoe rdvea
of Sars,1 but the absence of cilia in the latter species and other characters distinguish it.
4. Lagisoa extenuata, Grube, 1840 (?).
Specific Characters.—Length about one and a quarter inches in spirit. Head with a
deep median groove and two prominent peaks; eyes comparatively large, two in front
of the nuchal collar, and two larger in front of the middle line, and lateral in position.
Median tentacle somewhat long, scarcely dilated below the filiform tip, and with
moderately long cilia. Lateral tentacles short, with attenuate tips. Tentacular cirri
similar to the median tentacle. Palpi have rows of minute conical papillæ. Scales fifteen
pairs, rounded in front, reniform posteriorly, densely covered with minute spines, and the
free edge is profusely ciliated. Dorsal bristles strong, slightly curved, and closely
spinous, with a smooth spear-shaped tip ; ventral with a bifid tip and close rows of
spines, the tips of some at the ventral edge being simple. Dorsal cirri somewhat slender,
with numerous and slightly tapered cilia with bulbous tips. Ventral cirri stout, with
short cilia. Segmental (nephridial) papilla scarcely distinct.
S yno nyms.
1840. Polynoë extenuata, Grube. Actin., Bchin., u. Würmer, p. 86 (?).
1861. „ cirrata (O. F. M.), Grube. Ausflug nach Triest., p. 81.
1865, Lepidonotus Leachii, De Quatrefages. Ann., p. 258 ?
,, „ d/wmetosus, Ibid. Annel., t. i, p. 259 (?).
1867. Lagisca Ehlersii, Malmgren. Ann. Poly eh., 9.
1868. Polynoë extenuata, Claparède. Ann. Nap., 70, pi. ii, fig. 2.
1870. „ „ Supp., p. 372:
1875. ,, ,, Marion and Bobretzky. Ann. Sc. Nat., 1875, p. 6.
,, Lagisca extenuata, Marenzeller. Zur Kennt. Adriat. Annel., p. 5, Taf. i, f. 1.
1876. ,, Jeffreysii, McIntosh. Trans. Z. S., ix, p. 397, pi. lxxi, f. 8, 9, 11, and 12 ; pi. lxxiii,
f. 17 and 18.
1884. „ extenuata, V. Carus. Fauna Medit., 202.
1888. ,, „ De St. Joseph. Ann. d. Sc. Nat. (7), v, p. 180, pi. viii, f. 52—54.
1890. ,, „ Malaquin. Ann. Boulon., 22.
1891. Polynoe {Lagisca) extenuata, Hornell. Op. cit., 12, pi. xiii, f. 4 and 8.
1898. Lagisca extenuata, De St. Joseph. Ann. d. Sc. Nat. (8), v, p. 237,
Habitat.—A common Mediterranean form procured in the 1 Porcupine ’ Expedition
of 1869, in the tube of an Eunice, in 173 fathoms off the west coast of Ireland, and also
in a free condition on the same ground—muddy sand. Next year (1870) it was dredged
at the depth of 690 fathoms in the Atlantic (Channel slope).
It is also a tidal form on the eastern border of the Irish Sea.
Geol. og Zool. Reise/ 1862, p. 39.