terminal feet. At the tail the tips of the attenuate ventral bristles become much
elongated, some, however, maintaining, the typical outline.
The dorsal cirri spring from the posterior border of the foot, and in those feet
without scales a well-marked papilla, the homologue of the scale-peduncle, occurs at the
inner border of the basal process of the cirri. They are somewhat slender, and have
numerous and slightly tapered cilia with a bulbous tip. The cilia are shorter inferiorly
above the base, and again distally, and they cease about the middle of the filiform tip.
Posteriorly the cirri become longer and more slender, and the cilia more attenuate.
The caudal cirri are also slender. The long first ventral cirrus is stout, with a distinct
enlargement below the tip, which is much less filiform than the dorsal. The cilia, which
are considerably shorter and more uniform in length than those on the dorsal cirri,
extend from the base beyond the middle of the terminal slender region. They are
slender processes with a bulbous tip.
Loxosomae occur at the bases of the bristles and algaa with other forms on them.
In Grube’s original description of Polynoe extenuata1 the scales are entered as
smooth at the edge, and with minute warts. The inferior bristles are a fourth longer
than the upper. Colour brownish grey above, bluish iridescent beneath. Elytra
caducous. There is nothing to give certainty.
Baron de St. Joseph (1888) found one. in the tube of Serpula vermienlaris, but it
may have simply crept there for temporary shelter. He is of opinion it is closely allied
to Lagisca floccosa.
Hornell (1891) describes apparently the same form from the Liverpool district,
though his figure of the dorsal bristles is rather indefinite. Its relation to JEvarne impair,
to which he refers, is less marked than to Lagisca floccosa. The figure of the scale given
by this author differs from those procured by the ‘ Porcupine.’
This form would seem to be nearly allied to Grube’s P. extenuata as described
by Marenzeller in his ‘ Adriatic Annelida.’3 He does not give the minute details nor
describe the special condition in the tips of the upper bristles, which are longer in his
figure and more distinctly bifid than in the British examples. On the whole-the latter
would seem to be a well-marked variety, in which the secondary process of the ventral
bristles was less developed.
De St. Joseph (1878),3 after Langerhans, would make Lagisca rarispina and L.
propingua, Malmgren, varieties of this species—a view which the preceding descriptions
and figures will sufficiently criticise. He had the advantage of the specimens in the
Parisian Museum in identifying Lepidonotus Leachii and L. dumetosus, both of De
Quatrefages, with Lagisca extenuata.
i f Actin., Echin., u. Wiir./ p. 86, 1840.
8 Op. cit., 1898, p. 288.
Genus XII.—Acanthicolepis (Norman MS.); 1 Dasylepis, Malmgren, 1867.
Body elongate-oblong or sublinear. Head produced anteriorly into two pointed lobes
on each side of the median tentacle, below the base of which the lateral tentacles spring.
Eyes as in Eunoa. Scales eighteen pairs, coarsely spinous, overlapping each other
and covering the entire dorsum. Dorsal bristles stronger than the ventral, tapering
from the middle to the tip. Yentral bristles with short, bare, hooked tips, above the
spinous rows, with a minute secondary process in some towards the upper third of the
series. Segmental eminence distinct, papilla somewhat long and slender anteriorly, short
posteriorly.
Acanthicolepis asperrima, Gars, 1860.
Specific Characters.—Body rather broad and thick, tapered slightly anteriorly, and
still more posteriorly. Segments about forty-one. Eyes large, visible from the dorsum,
two in front of the nuchal fold, and two somewhat lateral in position about the middle
of the head, or perhaps a little anterior to it. Palpi of moderate length (in spirit), with
minute cylindrical papillse. The other appendages of the head have a slight enlargement
below the long tapering tip, the region above and below the enlargement having long
cilia. Tentacle and dorsal cirri similar. The ventral cirri are of moderate length, and
have short cilia. Scales eighteen pairs; the first pair rounded, the rest more or less
reniform, roughened, with long and strong horny spines, especially towards the free
border. The tips of the spines are often bifid.
Habitat.—The only British locality seems to be the Frith of Clyde, where it was
obtained by the veteran naturalist of that region, Dr. D. Robertson. It ranges to
Norway, where it was procured by Sars, and lately by Canon Norman in his productive
dredgings.
S ynonyms.
1860. Polynoe asperrima, Sars. Fork. Vid. Selsk. Christ., 1860, p. 59.
1865. Lepidonotus pharetratus ? Baird. Johnst. Cat., B. M. Suppl., p. 340.
1867. Dasylepis asperrima, Malmgren. Ann. Pdlych., p. 7.
1873.
1876.
1879.
1883.
Sars. Bid. Christ. Faun., p. 2.
McIntosh. Trans. Z. S., ix, p. 374, pi. Ixvii, f. 9—11.
Tauber. Ann. Dame., 82.
Levinsen. Nord. Annul. Yidensk. Meddel. f. d. Nat. For. i Kiobenhavn,
188 and 195.
The length of the example in the British Museum is about an inch.
The head (Plate XXYII, fig. 6) is somewhat longer than broad, with a well-marked
1 As the title Dasylepis has been pre-occupied by Pander for a Silurian Ganoid (1856), the
name suggested by Canon Norman, viz. Acanthicolepis, may be substituted.