is to be found in different specimens in this lower angle ; and when very obtuse a much
smaller relative proportion of the length of the plate lies below a horizontal line drawn
through the lateral angles, than is the case when the proximal angle is smaller.
The first brachial joint is short and cuneiform; the second often as long as, or even
longer than, broad; the proximal margin forming a fairly acute angle in the profile
contour of the plate. This joint has also the appearance of being very considerably
twisted round to the front; so that the afore-mentioned proximal angle is found opposite
the middle part of the margin of the horizontal suture of the first brachial, when seen
from the front. }' The third brachial is a comparatively short joint, of nearly equal
length at either side, and bears the first syzygy. The succeeding joints of the ray have
their longer side shorter than their breadth, and taper wedge-form to the other side*—
their profile, when seen from the exact median line of the ray, being regularly triangular.
On the lower portion of the ray, the angle formed by the longer side of the arm-joints
and the proximal suture is prolonged into a prominent peak, which is also brought
somewhat forwards. The neighbouring joint has a little corresponding projection or
lip, upon which this articulates; and owing to this structure, a semitubercular or knobby
character is given to the lower portion of the ray, which is highly characteristic of the
present species. The rays are very robust, and maintain this character throughout.
Towards the extremities the joints become very short, and their breadth equal to
several times the length of their longer side. Syzygies occur on the 3rd, 8th, 12th,
15th, 18th brachial joint, and so on—the first two being very constant, the third sometimes
varying onto the 11th or 13th joint; in the latter case the next syzygy does
not occur till the 18th brachial is reached.
The pinnules are very robust, 100 being present on the one side of an arm of a
moderate-sized specimen; and the joints are more or less compressed. The first five or
six upon the ray have the flattened dorsal prominences which give the peculiar saw-like
character mentioned by Müller and others. As a rule, the lowest pinnules in this species
are of fairly uniform length, increasing slightly as they proceed along the ray; sometimes,
however, the first pinnule is somewhat longer than its immediate successors ;
but there is no great disparity in the second and third, such as occurs in the two next
species.
In a first pinnule, measuring 20 millims., were 45 joints; in another, a fraction
longer, 48 joints; and the third and fifth pinnules measured, within a fraction, the same
length. A pinnule taken midway along the ray was 25 millims., and had 36 joints—in
this position the joints being relatively longer and more cylindrical, and their distal
margin finely denticulate. In all the pinnules after the first eight or ten, the two
lowest joints are very much larger than the rest, and they maintain this disparity
throughout the ray; their form, also, is noteworthy, the first or articulatory joint being
very compressed and somewhat halfmoon-shaped, whilst the proximal margin of the
second joint is also considerably incurved, so that a large vacant space is left between
the two joints, which is occupied by muscle or ligament,—these first two joints being
the only ones that preserve along the ray the slightest trace' of the dorsal carin«,
which have been mentioned above as characteristic of the joints of the entire
pinnule at the commencement of the series. The ovarial sacs attached to the pinnules
are large and thick—a circumstance which, in conjunction with the closeness of the
pinnules to one another, adds to the compact and dense character of the plume as a
whole.
The dorsal cirri are long and robust; and the joints are slightly compressed. Considerable
variation occurs in the length and in the number of the joints. A long
example measuring 60 millims., contained 42 joints; and another, on the same specimen,
about half that length, had 32. The longest joints, which commence at about the
12th from the base, are twice as long as broad, and are somewhat dicebox-shaped,
the proportion of length to breadth diminishing rapidly towards the extremity. The
terminal joint consists of a robust claw as long as the preceding joint; the penultimate
joint bears no secondary claw, but simply has the margin thickened and produced.into
a sharp angle—a development which also occurs to a certain extent on several of the
preceding joints.
Locality.—Franklin-Pierce Bay (F&ilden).
Description o f the Illustrations o f this Species on Plate VI.
Fig. 1. Antedon Eschrichtii: natural size.
2. Diagrammatic sketch of the radial plates.
3. Extremity of one of the dorsal cirri: magnified.
4. A first pinnule: magnified.
A n tedon celtica (Barrett), Norman. Plate VI, fig s . 5 & 6.
1857. Comatula Woodwardii, Barrett, Ann. & Mag. Nat. Hist. ser. 2, vol. xix. p. 32, pi. vii. f. 1 (non
Forbes)'.
1857. Comatula celtica, Barrett, Ann. & Mag. Nat. Hist. ser. 2, vol. xx. p, 44.
1865. Antedon celticus, Norman, Ann. & Mag. Nat. Hist. ser. 3, vol. xv. p. 104.
. 1877. Antedon celticus, Marenzeller, Denksch. k. Akad. Wissensch. Wien, Bd. xxxv. p. 24 (separate copy);
Dorsocentral semiglobular or hemispherical, and somewhat flattened*. Sixty
to seventy cirrus-pits may be traced on the specimens under notice. A cirrus
measuring 40 millims. in length has 38 joints: these are somewhat flattened; and the
longest occurs at about the 9th or 10th, which is twice as long as broad—this proportion
gradually decreasing as they approach the extremity, where the breadth is greater
than the length. The terminal joint is a robust claw, longer than the preceding joint,
which has the opposed margin angulated and sharpened, hut not enough to form a
secondary claw. In the smaller cirri, however, this sharpened joint is more conspicuous.
In the shorter cirri, which are scarcely half the length of those above
mentioned, the average number of joints is about 25, and the distal extremity of each
joint is broader than the proximal which next succeeds, in a more marked degree than
in the older cirri.
* Mr. P. Herbert Carpenter has figured and described this piece as elongate and conoid in young specimens
(Trans. Linn. Soc. Zool. ser. 2, vol. ii. p. 61, pi. iv. fig. 8). No trace of this shape remains in our
examples, which measure about 135 millims. in length.
■L 2-,