their very distinct oral reentering curve, produce as a series a beautiful festooning,
the well-developed front lower arm-plate entering into the circle; for the side mouth-
shields come up close to its flanks.
The jaws are small, short, narrow, and gibbous inferiorly, and are fringed with
mouth-papillse, one of which, or the homologue of a tooth-papilla, is large and
solitary. This is larger than the others, is often spear-headed; and there are usually
three smaller ones on either side of the jaws. As a rule, all these mouth-papillae vary
much in size and shape, and project obliquely downwards. The true teeth are angular
and broadly spear-headed in outline; and they are in a single series of at least five.
The first lower arm-plate is either unlike the others in shape and is perfectly or
irregularly elliptical, being broader than long from the oral to the aboral edge, or it is
heart-shaped and broadest distally and truncated orally. The second and lower arm-
plates are triangular, broad distally, where there is a bold curve, and angular orally,
the sides sloping, with scarcely any reentering curve ; the length and breadth are about
equal. The next and following plates retain their oral angle and broad distal curve,
which is sometimes notched in the median line; but the sides near the distal comers
are at first parallel and form a space for the tentacle, and then they slope in with more
or less of a reentering curve to the angle. Far out they become smaller and smaller
and fan-shaped, with reentering curves on the sides, and often have a slight notch.
The side arm-plates unite under the arm, and become longer and longer until they
occupy most of the under surface. After the fourth or fifth tentacle-opening there
is one small scale, or, rather, conico-cylindrical and blunt small spine. The first
visible tentacle-opening has four, and rarely five, scales on either side of i t ; the next
has some (three) rudimentary scales on the lower arm-plate, and one larger and flat
scale on the side arm-plate; under the next lower arm-plate there is often a rudimentary
scale, besides the fully developed one on the side arm-plate.
The arm-spines, three in number on mid arm, are slender; and the upper one is
the longest. There is a row of blunt and distinct small spinules (much smaller than
those in relation to the radial shields) on one side of the generative slit; but they are
large in relation to those of other species.
Lyman, after noticing that Ofhioglypha robusta differs from the other species of
the genus in its short, broad mouth-shields and finely tapering arms, states that it has
been found even in the high latitude of Wellington Channel. He quotes A. E.
Verrill, who states that its range generally is from low-water mark to 18 fathoms.
Lyman’s description of the typical specimen and of some varieties may be read with
great advantage.
Description o f the Illustrations o f this Species on Plate IV.
Fig. 5. The species, natural size, from above.
6. The under surface of the disk : magnified.
7. The upper surface of the disk : magnified.
Genus OPHIOCTEN, LutJcen.
Ophiocten, Liitken, Vid. Meddel. 1854.
Disk very flat, with margin forming a -sharp angle ^hovered with imbricating
scales and a superficial squamo-granular layer, through which only portions of the
radial shields and primary plates are visible. No disk-incisions, the disk forming a
little arch over the' base of the arms. A row of papillae edges the genital slit, and
passes over the arm along the disk-margin, continuous with the series from theffiher
side. The mouth-shields are scutiform, and are prolonged into the interbrachial space.
The first group of tentacle-scales pass inwards, close to the angle of the jaws. Three
arm-spines, arranged along the outer edge of the side arm-plate, the two upper spines
being much the largest.
Ophiocten sebioetjm, Forbes, sp, Plate IV, Figs. 8.-10,14,
Ophiocten Krceyeri, Liitken, Vid. Meddel. 1854, p. 8-.
Ophiura sericea, Forbes, Sutherland’s Joum. Voyage Baffin’s Bay, Appendix.
A typical specimen should have the outline of the disk, seen from above, perfectly
circular, without arm-notches and without straight lines to the margin of the interradial
areas. The disk is slightly tumid above; and the sharp margin merges into a more
largely scaled and flatter under-disk. Disk tessellated with circular plates, one in the
centre, five around at some distance, and a few others, but all separate and ornamented
with radiating lines of cells, all being surrounded and overlapped by a derm of minute
circular scales cellular in aspect. The radial shields, which are wide apart, are larger
than the other plates, narrowest aborally and broadest within; obliquely placed, their
distal end being arched and free ; and between them, under the derm, are some rudimentary
upper arm?plates. There are distinct radial scales projecting beyond the radial
shields; and on their distal edge from 5 to 7 spinules with narrow bases, swollen cylindro-
conical trunks, and rather angular and sharp terminations are visible. These are in
a row; and there are others in some instances projecting from the cells of the derm
between the radial shields, and, deeper still, from the rudimentary upper arm-plates.
The upper arm-plates, broad, short, and convex near the disk, form much of the
arm; and usually the first five or six large ones are covered with a row of smaller
spinules than those on the edge of the disk, which project along the line of, and close
to, the arm, extending, in some, along the whole distal curve. After the fourth they
diminish in number; and one or two only are seen on the six arm-plates further out.
The upper arm-plates increase gradually in length, and only diminish in breadth
far out, and at last become more or less triangular in outline, whilst quite at the top they
are long, narrow, triangular, and separated by the side arm-plate. In some specimens
there are no spinules on the upper arm-plates.
Beneath, the scaling is larger and overlapping in the interbrachial spaces, and is