Feet.—The tufts of bristles from the first foot project somewhat outward dorsally,
obliquely inward ventrally. They all appear to belong to the dorsal type, consisting of
long, slender, finely serrated bristles with hair-like tips. The dorsal tuft is the longer;
the inferior, moreover, presenting proportionally more of the smooth shaft at the base.
The dorsal group alone possess a spine, and Pruvot and Racovitza consider the inferior
group as representing the ventral tuft.
The second foot has its dorsal lobe only slightly separated from the ventral, but the
spine has a special free papilla. Just above it three extremely elongated papillae
(stylodes) project from a common base. A long tuft of dorsal bristles—very finely
serrated—arises from this lobe. They are directed forwards and inwards. The ventral
division of the foot is bluntly rounded, extends further outward than the dorsal, and
bears three groups of long papillae, each springing from a basal process. The first arises
from the tip above the spine, and has attached to it about four long papillae, the longest of
which projects further than the dorsal, since its basal process is carried out by 4<he ventral
division. The knob enclosing the spine gives attachment also to four, while a prominent
peduncle just above the group of slender inferior bristles carries three. All these
processes are somewhat translucent, granular, and with a cellulo-granular and almost
transparent tip. The upper ventral bristles have tips of great length and tenuity, no less
than about twenty divisions occurring in the terminal appendage, which is capillary at the
tip, and, if fringed with minute algae, it resembles a pinnate hair.
The feet gradually merge into the typical form (Plate XXXI, fig. 6), which dorsally
below the branchial process shows three ciliated pads (ctenidia), and a few small clavate
papillae on the region between them and the bristles. This (dorsal) lobe is somewhat clavate
in outline, and has four or five long papillae (stylodes) from its upper terminal region, the
spine passing out inferiorly. The bristles are slender, long, finely spinous, tapered, and
form a fan directed upwards, outwards, and slightly backwards. Parasitic structures
are common on these bristles.
The ventral division is shorter and broader than the superior, and is somewhat
conical at the tip, while a large flattened and leaf-like lobule projects above the spine,
and a smaller lobule at the ventral edge. The large lobule shows a process or papilla
extending beyond it, and in its granular epidermic layer are large glandular areolas. The
superior ventral bristles have the type of those in S. boa, only more slender. They are
simple tapering bristles with bold spinous rows at first, and then more minutely spinous
towards the slender tip (Plate XLII, fig. 1). Beneath are a few with stout curved shafts,
a short bifid terminal region, and a single articulation (Plate XLII, fig. 1), an arrangement
which also occurs in the following three or four segments. The next are rather
slender bristles with long tapering tips, having from nine to nearly twenty segments
(Plate XLII, fig. 2) with a minute hook at the tip. Then follows a stouter series
(Plate XLII, fig. 3) with long tips, also bifid, the shafts becoming more slender as we
proceed downward; and lastly, a much more delicate group at the ventral edge,,with
from five to ten segments in the terminal region, which also has a minutely bifid tip.
The ventral cirrus is long and tapered, with a terminal segment (Plate XLII, fig. 4),
or occasionally two.
In the posterior feet little change takes place in the dorsal lobe, except a diminution
in the number of papillæ. In the inferior division the flattened lobe becomes a much
smaller rounded process above the spine, and has a large papilla attached to it superiorly.
The simple spinous bristles of this lobe disappear, and a few bearing three rows of spines
on the end of the shaft and a terminal division of three segments occur, the tip being
simple. Others show four articulations. Above and below the spine are stouter bristles
having tips of a single joint, or of two or three, strongly bifid, and this condition holds
in front in certain Norwegian examples.
The slender inferior series show very delicate tips, with about four joints and simple
hair-like extremities. The lobe beneath the spine in these feet does not diminish so
much in proportion as that above it.
. Reproduction.—Specimens tossed on the beach at St. Andrews in February had
numerous large ova, so that the reproductive period would seem to be early spring.
Habits.—It appears to be a dweller in sand, and is somewhat sluggish in confinement.
The finest specimens in my collection came from St. Andrews, but those from Shetland
and Polperro are also of considerable size.
Dalyell’s Aphrodita arcta may be this species, or an allied form. Unfortunately no
distinctive feature is given.
The Sthenelais leiolepis of Claparède, from Naples, approaches this species in the
form of the scale, as pointed out by the Swiss author. I t is distinguished from it by the
occurrence of only one ciliated mammilla below the branchia. Pruvot and E-acovitza unite
them, and consider'the distinctions rested on imperfect observations.
5. Sthenelais J effreysii, McIntosh, 1876.
Specific Characters.—Head broadly ovate, with a median ridge running forward to
the base of the tentacle, which is longer and thicker than in S. limicola. Lateral regions
of the head form smooth ovoid lobes. No eyes in the preparation. The massive first
foot carries dorsally the lateral tentacle interna! to the bristle-bundle, and the dorsal
cirrus externally, both extending beyond the tips of the bristles. Just beneath the
former is the lamellar process, while ventrally is the shorter and more slender ventral
cirrus. The long, smooth, tapering palpus, with its sheath-like lamella at the base—
superiorly and internally—arises below the process. Body narrow, probably about two
inches in length, and with numerous segments. Scales smooth, translucent, and devoid
of pigment in the preparation; first pair probably rounded, rest reniform. On the
external border are long, slightly tapered papillse, perhaps more numerous in the anterior
scales, and they may disappear posteriorly. The foot has a branchial process, and three
ciliated pads (ctenidia) along the upper edge. The dorsal lobe is somewhat clavate,
bevelled at the tip, with three long papillm, and a tuft of tapering bristles bearing fine and
rather closely set rows of spines. The ventral division has a conical tip, with one or two
papillse at the apex, and one on each of the lobes. The upper ventral bristles have four
rows of spines on the distal end of the shaft, and a most delicate tapering terminal
process of twelve to fifteen articulations ending in a hair-like tip. Below the spine the