The three radial plates are visible; the first is a very short band-like plate at the
margin of the centrodorsal; the second is comparatively long, and diminishes with a
somewhat rapid but graceful curve into a neck-like form at the distal extremity, upon
which the axillary radial is articulated; and there occurs in the median dorsal line a
slight prominence or lip opposed to the proximal angle of the axillary. This latter,
which is the third radial plate, is quadrately diamond-shaped in its outer contour,
and somewhat broader than long, the distal angle being more obtuse and the margins
of the distal facets much less incurved than in the preceding species. The first
brachials are also relatively longer and more conspicuous than in A. JEschrichtii; and
the second brachials are subtriangular or even subcrescentiform in profile (as seen from
outside), and are broader than long, their apex being brought forward very considerably
to the front, The third brachial, which bears the first syzygy, is nearly as long as
broad. At some distance from the disk the joints of the ray are almost as long at their
deepest part (i. e. on their longer side) as they are broad,- the length of the shorter side
being, perhaps, rather more than one third of the breadth on the lower third of the
ray. The sutures of the joints are not nearly so much inclined as in A. JEschrichtii; and
the joints diminish in length as they approach the extremity of the ray. Syzygies
occur normally on the 3rd, 8th, 12th, 15th brachial, and so on—although the second is
sometimes found on the 9th, the third on the 13th or 14th, and the fourth on the 16th
or 17th brachial joint.
80-90 pinnules occur along one side of a ray. The arms, as a whole, are long,
tapering, and decidedly delicate in character, although so numerously pinnulated;
whilst the narrowness of the calyx, the angle of ray-attachment, and the comparative
shortness of the pinnules give a very long and narrow appearance to the closed plume.
The first and second pinnules are equal in length, measuring 15 millims., and
contain 36 joints each. The third pinnule is very much smaller, being scarcely
11 millims. long, and with only 23 joints. One from the middle of the ray has likewise
23 joints, and measures 15 to 16 millims. long. In another specimen the first
pinnule had 37 joints, and the third 18. The joints on the proximal third of the first
three pinnules have the dorsal side produced into flattened processes, similar to those
developed much more prominentlyJ.n the last species. The pinnules beyond the first
three have very much longer joints, as will be seen by reference to the measures
above given; and these are also more cylindrical in shape. In these pinnules, furthermore,
the first two joints are much flatter, broader, and shorter than the rest, but do not
present the conspicuous character noted in A. JEschrichtii. The ovarial sacs are thin,
delicate, and semitransparent, presenting a very marked difference in comparison with
those of the latter species.
Remarks.—It is not without considerable hesitation that we have referred the form
under notice to Barrett’s species; for the original diagnosis is so meagre that little can
be made out of it. Dr. Marenzeller, however, has given a perfectly intelligible and
more comprehensive sketch of (what is in our opinion) the same species, in the
description which accompanies his determination of examples obtained by the Austro-
Hungarian Arctic Expedition, with which specimens ours would seem to accord in all
essential particulars.
Mr. P. Herbert Carpenter (loc. cit.) has entered with great care and detail into
certain parts of the anatomical structure of a Comatula referred to under this name;
but no other writer, excepting those mentioned above, appears to have spoken of
A. celtica from a systematist’s point of view*.
Locality, &c.—Discovery Bay, lat. 81° 41' N., 25 fathoms, hard bottom (Feilden);
Franklin-Pierce Bay.
Description o f the Illustrations o f this Species on Plate VI.
Fig. 5. Antedon celtica: natural size.
6. Diagrammatic sketch of the radial plates.
A n tedon prolixa, Sladen, sp. nov. Plate VI, Figs. 7-10.
Dorsocentral very conoid, as long as, or longer than, broad, with four or five tiers
of cirri arranged one above the other, about 60 to 70-all together being present;
the apex having no pits, and presenting the appearance of a sort of tubercular boss.
The cirri are remarkably long and delicate—one, with the extremity missing, measuring
58 millims. Another, 47 millims. long, has forty joints; and this appears to be the
average length and number. One of the small cirri (which is 21 millims.) has twenty-
nine joints. The joints of the cirri are very long and cylindrical, but narrower in the
middle than at the extremities; the eighth from the basal joint measures 1*76 millim.
long and ‘43 millim. broad, or four times as long as broad; the terminal joint is
modified into a delicate claw; and no actual secondary claw occurs at the extremity of
the penultimate joint, only a slightly produced triangular peak.
The first radial is not visible in front, only at the extreme sides, where it may be
seen rising up towards the interior. The second radial is of moderate length, nearly as
long at the sides as broad, and is not much (if at all) constricted at the distal extremity.
The third or axillary radial is very regularly quadriform, placed diamond-wise (the
length being about equal to the breadth), and with all the sides incurved. The first
brachial is comparatively long; the second longer than broad, and subtriangular in
profile from the outside, the proximal angle remaining in a much more lateral position
than in either of the preceding species; the third brachial, which bears the first syzygy,
is as long as, or longer than, broad; and the succeeding joints of the ray are all
comparatively long, and increase in relative length towards the extremity of the ray.
Syzygies occur normally on the 3rd, 8th, 12th, and every third joint beyond.
On the whole it may be said that the radials stand very high in this species, and
that the rays spring off from them well separated into pairs—the rays being comparatively
thin and delicate in habit, and the pinnules being seemingly placed wide apart, in
consequence of the length of the. joints.
* Since writing the above, we have had the opportunity of examining specimens which we owe to the
kindness of Sir Wyville Thomson, and which he, in common with other British naturalists, has been in the
habit of regarding as the representatives of A . celtica. They are altogether different from the Comatula here
described, and resemble to a certain degree the form that we have named A . prolixa, but from both of which
they are, in our estimation, a perfectly distinct species.