Ophioglypha Sarsii, Liitken, sp. Plate IV, Figs. 3, 4.
Ophiogh/pka Sarsii, Liitkon, Yidenskabslig© Moddololser. fra dsn aturhistoriake Porening iHjdbQnliavn,
November 1854.
An Ophioglypha with mouth-shields shield-shaped, longer than broad; length less
than, or only equal to, their distance from the margin of the disk. Papillae of the
disk-incision about fifteen and rather broad. Under arm-plates widely separate, of a
very broad, short triangle-shape. Two tentacle-scales. No infrabrachial indentations.
Spines rather long, equal in length to the side arm-plates.
This is the most northerly Echinoderm brought home by the Expedition, a fine
specimen, with a disk-diameter of 26 millims., having been taken by Capt. Feilden at
the winter-quarters of H.M.S. ‘ Alert,’ in N. lat. 82° 27', in 10 fathoms. Other
examples of this species were obtained at Discovery Bay in 25 fathoms, and among
them one which is provided with remarkably long arm-spines, being in relative
proportion fully twice the length of the spines generally occurring in Ophioglypha
Sarsii. In this individual the three spines of the sixth joint measure respectively
2-45 millims., 2*25 millims., 1-4 millim., the under arm-plate being 0-7 millim. long,
the arm-joint 1 millim., and the disk-diameter 15 millims. The remaining features of
the specimen agree too closely with the characters of Ophioglypha Sarsii (Liitken, sp.),
in our opinion, to warrant its removal from that species, even as a provisional variety.
Specimens were also found off Hayes Point.
In some cases great irregularity is exhibited in the mouth-papillae, one abnormal
example being particularly worthy of notice. In the Ophioglyphce the innermost
mouth-papilla generally stands immediately under the teeth, and might be easily
mistaken for a tooth, being, in fact, affixed to the tooth-plate and not to the lateral
plates. In 0. Sarsii, as well as in other members of the genus, two additional
papillae are generally associated with it, one on either hand, and are in like manner
borne by the ossicle upon which the teeth are placed.
In consequence of this arrangement it has long seemed probable to us that these
subdental papillae should be regarded as tooth-papillae (of which they are in truth the
homologues) rather than as mouth-papillae so-called, along with which they are
commonly counted. One of the specimens taken in Discovery Bay throws considerable
light upon this question.
In this individual the d.ental armature consists of four teeth regularly superposed,
following upon which, and occupying the same breadth as a tooth, are three ossicles
which fit to. one another, wedgewise, with sloping sides. Then come two which fit
together and correspond in their shape with the irregularities of the upper and under
tier, which latter consists of from three to five compact, close-fitting papillae ; and these
again are succeeded by three or four (in some rays five) moderately long, round-tipped,
smaller papillae, the whole forming a compact mass suggestive, in the highest degree,
of ordinary tooth-papillae, such as occur, for instance, in Ophiothrix; and yet in every
detail, even to measurements, the specimen conforms to the diagnosis of Ophioglypha
Sarsii. This individual has a disk-diameter of 22 millimetres.
Bearing in mind the tendency towards vertical reduplication of the mouth-
papillae in some genera, this cannot fail to be regarded as suggestive of the manner in
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which primitive tooth-papillae may have been developed; nor is such an assumption
by any means extravagant when the great irregularity of these parts amongst Arctic
forms is taken into consideration.
The specimen of Ophioglypha Sarsii, the teeth of which have been alluded to as
being abnormal, is dry and of a dirty white colour. The disk has a pentagonal outline
above, but is circular below; the notches for the arms in the upper part of the disk
are distinct; and the scaling is small. There is a small circular scale centrally; and
the radial shields are embedded, as it were, except at their outer extremity. Several
scales separate the radial shields, some being larger than the others. The radial shields
•are separated aborally, by a linear groove, from distinct radial scales. These bear the
majority of the flat, broad, closely-set spinules, which are continued on the interbrachial
space below, along the generative slit, and finally touch the sides of the mouth-shield.
A corresponding series of much smaller, adpressed and blunt spinules is on the side
arms close to the others; and it can be traced, as a ragged dentate border, to the generative
slit, close to the arm on the under surface of the disk. Three or four small upper arm-
plates exist before the full-sized fifth is seen; and they are more or less within the
notch; and their aboral edges are very faintly incised. Below, the mouth-shields have
the usual shape of those of the species, and the. side mouth-shields are small, and their
outer and aboral part is in contact with the generative slit. About six close, short,
blunt scales are on, each, and are opposed to a smaller number of slightly larger
tentacle-scales on the arm; and the tentacular opening (the 1st visible but the
2nd really) is long. The jaws are very short, stout, and lumpy inferiorly; and the jaw-
plate is, small. The mouth-papillse, usually so symmetrical, are placed obliquely, are
irregular; and the usual central one is replaced by from four to six smaller ones,
which have been noticed before. The underpart of the side arm-plates near the
disk somewhat resembles that of Ophioglypha lacertosa, Forbes, sp., being almost
perforated where the oral angle of the under arm-plate nearly of quite touches the
aboral edge of its predecessor. Union of the side arm-plates below, occurs at about
the sixth or seventh. The three arm-spines are small, irregular in shape, are adpressed,
rounded, and rather flat; sometimes a fourth is seen; and all are slightly constricted
above their origin. Two tentacle-scales exist to the end of the arm; but in some
joints there are three, or even four, small scales. In mid arm the tentacle-scales are
on the side arm-plates only; one is short, broad, flat, and narrowed at its origin, and
is internal to the other. Each either resembles a small conico-cylindrical spine, or is
more like the first. In the neighbourhood of the disk the narrow peduncled and
broad, short, blunted tentacle-scales, normally two on. the side arm-plate over the
tentacular opening, have a third, placed flat against the under arm-plate, from which
it springs. Nearer the oral opening, the number of tentacular processes increases as
usual. Where only one tentacle-spine exists, it is broad, and appears to be double with
a common base.
Description o f the Illustrations o f this Species on Plate IV.
Fig. 3. Ophioglypha Sarsii, Liitken, the top : natural size.
4. Ophioglypha Sarsii, Liitken, the underpart of the disk.
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