stouter series follows, also with long bifid tips, the shafts becoming more slender in the
lower group. Lastly is a more delicate group at the ventral edge, having bifid distal
appendages of from five to ten articulations. The ventral cirrus is long and tapering,
with a terminal segment.
S ynonyms.
1853. Aphrodita arcta, Daïyell. Pow. Créât., ii, p. 170, pl. xxiv, f. 14.
1864. Sthenelais limicola, Ehlers. Borstenw., 120, Taf. iv, f. 4—7 ; Taf. v.
1868. „ leiolepis, Claparède. Ann. Chét. Map., 96, pl. iv, f. 8, and pl. vi, f. 1.
1869.
limicola, McIntosh. Trans. R. S. E., xxv, 410.
1875.
1876.
1884.
1891.
1895.
„ idem. Invert, and Fish., St. A., p. 118,
' ,, ' idem. Trans. Z. S., ix, pp. 390, 476, pl. lxx, f. 13.
„ Y. Carus. Faun. Medit., p. 205.
,, Homell. Op. cit., p. 238.
„ Pruvot and Racovitza. Arch. Zool. exper., p. 473, pl. xx, f. 122, 123.
Habitat—First dredged by Dr. G-wyn Jeffreys in sixty to eighty fathoms off
North TJnst, in St. Magnus Bay, and the Outer Haaf, Skerries, in Shetland in 1867. It
is very abundant off St. Andrews, probably in sand, and is tossed on shore in large
numbers during certain storms. While it is not common in the dredge, the cod seems
to find it readily, and so do the flounder and other fishes. In the ‘Porcupine’
Expedition of 1869 it occurred in 30 to 370 fathoms off the lrish coast, and a small
eyeless variety in 420 fathoms. I t ranges from Shetland to Cornwall, and has been
found chiefly in water of some depth,—never, at any rate, between tide-marks. It
extends likewise to Norway (Canon Norman), to Quarnero in the Adriatic, to the shores
of Canada, and the United States of America.
Head (Plate XXIX, fig. 3) somewhat ovoid in outline, with the long diameter
transverse. The median space is marked by a brownish crescentic line on each side,
which Ehlers compares to an H. The posterior pair of eyes are situated a little behind
the base of the median tentacle, are of considerable size, and sometimes show a pale
speck in the centre, as if from a corneal lens. The anterior pair are scarcely visible
from the dorsum (indeed, they escaped Ehlers), being situated under the lateral
processes (ctenidia) at the base (ceratophore) of the median tentacle, and looking
straight forward. They are somewhat larger than the posterior, and also occasionally
show a pale speck in the centre. The ceratophore of the median tentacle is somewhat
conical in spirit, but Ehlers says cylindrical in life, and from it a tapering tentacle
(ceratostyle) of moderate length passes. The filiform region shows a slight enlargement
at the tip in spirit, and a trace of an articulation at its commencement. On each side of
the base is a flattened spatulate process (ctenidium) with long cilia. The frontal lobe
carries ventrally the very long, tapering, smooth palpus, with a small sheath or
membranous collar at its base internally, then a slender filiform ventral cirrus ; dorsally a
much larger dorsal cirrus, and internally to the ventral cirrus a broad scimitar-shaped
process (cuilleron céphalique, Pruvot and Racovitza). A little behind and internal to the
dorsal cirrus is the tip of the lateral tentacle, which Racovitza followed backward to its
attachment to the head. In his description Ehlers omits the scoop-like process at the
base of the palpus. His view of the parts, indeed (Taf. iv, fig. 6), differs from what
our specimens would have exhibited in life.
ProboscisWj?The teeth are similar to those of 8. boa, the lower pair apparently
biting in front of the upper; but preparations are not always to be relied on in this respect.
The number of conical papillae dorsally and ventrally is eleven. I t is curious that few or
none eject the organ in spirit, whereas the gastric juice of the stomach of the cod causes
full protrusion, the broad end of the trumpet-shaped structure being distal. Moreover
a pair of oblique elevated ridges occur dorsally and ventrally near the tip.
Body.—The body is elongate, some of the imperfect specimens being nearly two
inches in length. Ehlers gives 57 mm. and 128 segments, and one of the contracted
perfect forms is larger than Ehlers’ examples. Pruvot and Racovitza record a length
of 95 mm., and a total breadth of 4 mm. I t tapers posteriorly to a delicate tail which
has two caudal cirri. The body is rounded dorsally, flattened ventrally. A segmental
eminence-•'occurs at the base of each foot, but no distinct papilla.
Scales numerous, translucent, rounded in front, irregularly ovate or somewhat
reniform posteriorly, and cover the back. They are of a light brownish hue, best marked
in front. They occur on segments 2, 4, 5, 7—25, and on all the others (Ehlers). The
first scale, which has the scar for attachment behind its centre, presents a series of short
clavate cilia along its outer border, and a few longer digit-like cilia at its anterior and
outer margin.1 Finely branched nerves pass from the scar throughout the scale. Its
surface is quite smooth. The typical anterior scale (Plate XXXIY, fig. 9) has externally
a thin folded margin possessing irregular processes, either simple, bifid, or divided into
several flaps. The surface is smooth, though often crossed in the preparations by fine
lines, probably creases or folds. Between the elytrophore and the anterior curvature, and
stretching on each side beyond, is a series of rounded bodies like papillaa (the “ petit
tubercles irréguliers ” of Pruvot and Racovitza), but they do not project from either
surface of the scale, and appear therefore to be internal, as a reference to the condition
in the posterior scales more clearly demonstrates.
The posterior scales (Plate XXXIY, fig. 10) are bilobed externally, each lobe
forming a rounded process, which either approaches its fellow over the T-shaped fissure
or slightly overlaps. Moreover in the terminal scale a belt of large vesicular organs
occurs in the granular layer of the epiderm, in front of the scar for attachment. They
consist of a large pale central region surrounded by a ring of smaller bodies. Each of the
large circular vesicles has a cell with a nucleus and nucleolus, and the ring seems to be
composed of nucleated granular cells. They indeed resemble papillas with a ring of
secondary processes at the tip, but they appear to be internal, and a further development
of the structures noted anteriorly. These continue to the posterior extremity.
At Banyuls Pruvot and Racovitza found a large transverse touch of brown on the
posterior region of the scales, and between the elytrophore and the anterior curve a
few *minute tubercles, best marked and most numerous in the posterior scales. As
above mentioned, however, these structures project neither from the dorsal nor the
ventral surface of the scale; they are vesicular and internal rather than tubercular and
external.
1 Neither Ehlers nor Pr.uvot and Racovitza mention these.