secondary process, so that the end is like a bird’s beak. Those at the ventral edge
again are much more slender, have a slightly dilated spinous region, and a five-jointed
bifid appendage. Two groups of clavate papillaa occur on the edge of the foot above
them and a row of smaller papillse at their bases ventrally. The ventral cirrus extends
fully as far as the fleshy part of the foot, and internal to it is a funnel-like, ciliated
process.
The typical foot (Plate XXXI, fig. 5) presents dorsally a richly ciliated branchial
process somewhat subulate in outline, and which is evident at the fourth foot. Beneath,
on the dorsal curve, are three T-shaped ctenidia. Another ctenidium lies on the posterior
border of the foot deeply placed in the interpedal fissure. In the middle of the body others
occur on the dorsum of the foot and behind the elytrophore. Pruvot and Racovitza observe
that they all have the same structure, viz. conical epidermic cells with their bases at the
broad end and their points at the pedicle of the organ; they are richly ciliated distally.
The dorsal lobe is considerably less than the ventral; the bristles (Plate XLI, fig. 19) are
long, slender, and boldly spinous from a little above the base to the tip. Viewed from the
side they form a beautiful fan directed laterally with the digit-like papillae at the anterior
border of the base. Though slender they are somewhat stiff and curved—-with the
concavity upward (Plate XLI, fig. 20). The spines form even transverse rows,
thus differing from the alternate series so common in this group and in the.
Polynoidaa. The transverse arrangement, however, may render them more brittle. The
dorsal lobe is separated from the ventral by a deep fissure, and has a series of long
papillae at its tip. The ventral lobe is massive, with a truncated-extremity which bears
the spine in its middle, and usually a single digit-like papilla. A fold of skin,
arising at the upper part of the lobe, passes down posteriorly and curves to the front,
separating the more slender ventral bristles from the stout series. In the posterior part
of the body the commencement of this ridge of skin forms a free flap. The upper group
of the ventral series consists of the moderately stout forms with the simple spinous tips
(Plate XLI, fig. 21), and also a few with about three joints to the tapering, bifid
appendage, the tip of the shaft having a few rows of spines. The centre of the foot is
occupied by a series of stout shafts bevelled at the tip, and with a short appendage of one
segment (Plate XLI, fig. 22), and the beak-like, bifid extremity. In some, transverse
strige indicate traces of spinous rows. Those of the upper series have longer and more
slender appendages. Ventrally is a group of slender bristles forming a row directed
forwards and outwards, then downwards and outwards, each with a few rows of spines
on the expanded distal end of the shaft and appendages of one to four joints (Plate XLI,
fig. 23). These spring from a notch at the ventral edge and within the tip of the foot,
the inner border of the notch being marked by a series of small papillae. In the region of
the spine, which pierces the middle of the foot, is a long and somewhat fusiform papilla.
So far as the structure of the bristles is concerned, the type remains the same in the
terminal feet, though the bristles diminish in size. The median stout bristles have longer
and more slender hooked appendages, and the backward curve of the end of the shaft
is more marked^ The papillae are fewer. The ventral cirrus is subulate and tapering,
extending to about the tip óf the fleshy part of the foot. A spur or process occurs at
its inner border above the basal segment.. A well-marked ctenidium is placed a little
internal and anterior to the cirrus. The dorsal hairs are prone to deposits of mud, algoid
growths, and stalked Infusoria, their colour thus being often brownish or greyish; while
Loxosomse abound on the feet, under the scales, and other parts.
Pruvot and Racovitza give a good figure,1 showing the arrangement of the lobes,
papillae, and bristles in a typical foot. Dorsally the papillaa (stylodes) occupy the
anterior region and pass beneath the division. Ventrally, the flaps, which they call
parapodial bracts, envelop the foot above and beneath, as well as superiorly in front, the
antero-inferior being scolloped, each process being terminated by a sensitive palpocil.
Reproduction.—Large specimens in the Channel Islands were laden in August with
fairly advanced greenish eggs in enormous numbers. The males had also the perivisceral
chamber charged with sperms, which issued, after immersion in spirit, from the
bases of the feet.
Development.—Larval forms occurred, towards the end of October, with bluish
anterior digestive organs in the metatroch stage, with two kinds of bristles,—viz.
long, curved, serrated bristles, somewhat like those of Polynoe, and shorter compound
forms. Viewed from the front superiorly (Plate XXVIa, fig. 22), two eyes lie on
each side. An oblique lateral view shows the feet of one side and the caudal cirri.
The first and last bristle-tufts are simple and short, and about seven pairs of feet are
visible. Only a single, long, and comparatively strong, swimming bristle occurs in each
foot, the curved tip being distinctly and somewhat widely serrated on the convex edge.
Such, therefore, would appear to be a modification of the serrate dorsal bristle, which is
functional at this stage. The ventral bristles had dilated ends to the shafts—with the
usual oblique termination and a distal region of two segments. I t is uncertain whether
these young forms pertained to this genus or to Sigalion.
Habits.—They are somewhat sluggish animals, usually lurking under stones between
tide-marks, where they rest on a sandy bottom, though occasionally small examples are
found in pure sand as at Southport. They form curious coils in vessels in confinement,
and appear to be nocturnal. So far as my specimens go, the finest are those between
tide-marks, Herm, while next to these, and only a very little less, are those between
tide-marks at St. Andrews. Those procured in the sand of the Zetlandic voes are much
smaller, and the same may be said of those from the outer Hebrides. Average examples
come from the west coast of Ireland.
This species was introduced, in 1833, to science by Dr. G. Johnston, who found it in
Berwick Bay under stones near low-water mark. He says it is somewhat sluggish, but
burrows in sand with rapidity. Moreover that it is the Goliath of its race, and preys on
its fellow-worms. I t is probable that Rathke, in 1843, referred to this species under
the title mentioned ($. Idunse). The Sthenelais Edwardsii of De Quatrefages (18(55)
seems to be this species. He placed next the foregoing the Sigalion Mathildse of
Audouin and Edwards, for he thought they included two species under that title. He
entered the Sthenelais Idunse of Rathke, and the S. boa of Johnston as separate species.
Langerhans (1880) describes Sthenelais Idunse from a depth of twenty fathoms off
Madeira. He points out the reddish colour of the head (from the brain), the ringed base of
1 Op. cit., p. 463, fig. 12.