in f
■ 1
f
I lk
i i j
Arms at least six times the diameter of the disk, not diminished
in width for some distance out. Just beyond the disk there are three
large upper and four much shorter spines : the lowest, which is the
smallest, is very sm a ll; gradually this disappears, and then the
following one gets smaller and smaller till it disappears. The upper
spines are faintly echinulated near their tip ; the uppermost but
one is generally rather the longest, but is never more than equal to
about the length of two of the upper arm-plates.
The edge of the genital slit is fringed by some elongated plates ;
the bridge is pretty w id e ; the mouth-shields are largo and stout,
rather longer than broad, and have a notch in the middle of their
inner edge.
The lower arm-plates have pretty even sides and are of about the
same length as breadth ; the tentacle-scale is only distinct at the
proximal end of the arm. The upper arm-plates are twice as broad
as long, broader along their distal than their proximal edge.
General colour of disk yellowish grey, the radial shields violet, the
upper arm-plates washed with slate-grey and having a faint white
line along their middle; the spines light-coloured, hut darker
towards their tip ; the actinal surface lig h te r; the mouth-shields
prominent by their whiteness.
Port Darwin.
23. Ophiothrix darwini.
Disk somewhat pentagonal, with delicate spines on its upper surface,
hut the radial shields naked. Colour light pink, green, or
lemon in places, with a few dark spots.
' Length of arms perhaps not more than six or seven times the
diameter of the disk.
The large radial shields form right-angled triangles, the perpendicular
side being separated from th at of its fellow by a very narrow
line and by only a single row of rare spines; a slight notch separates
the plates at the periphery of the disk. The interradial spaces
are about as broad as the base of the radial shields, and are richly
covered with delicate spinules, these extend on to the actinal surface,
but leave a bare band bordering the genital slits ; the bridge between
the slits is narrow ; mouth-shields broader than long, somewhat irregularly
lozenge-shaped in form. The lower arm-plates are very regularly
arranged, and are only slightly oblong, many being almost
completely square. The upper arm-plates are broader than long, the
aboral edge three-sided, the adoral sides long, and the consequent
form th at of a not very regular hexagon. Pour or five arm-spines,
the lowest not peculiarly short, and the uppermost equal to five
upper arm-plates in length, echinulated at their free end. There
appear to he two very small tentacle-scales.
The larger of the two specimens presents the following markings ;
—There are three black dots on each of the mouth-shields ; some of
the lower arm-plates are light green, the adoral edges of others are
marked by a black spot, and this is rendered the more conspicuous
by the fact th at two successive plates are so marked, and th at then
there is an interval of two or more not so distinguished. Three or
four blackish dots are to he found on the radial shields, along the
line of the vertical side; by pairs or threes the upper arm-plates are
faint pink or light green, and the pink ones are distinguished by
each having a black dot.
I have taken advantage of the locelity of this well-marked and
really beautiful species to associate with it a name honoured by
us all.
Port Darwin, 7 -12 fms., mud and sand.
24. Ophiothrix melanogramma.
Disk pentagonal in appearance, completely covered with fine
spinules, which are a good deal longer and rarer on the actinal surface.
Arms 4 -5 times the diameter of the disk, tapering very delicately
; the upper surface marked by a black line, which extends a
good way on to, but does not reach, the centre of the disk.
The radial shields are almost completely obscured by the spinu-
lation, which is very delicate ; mouth-shields broader than long, the
inner sides meeting at an acute angle, the outer edge rather evenly
rounded, the bridge between the genital slits very narrow; seven or
eight arm-spiues, the two lowest very small, the upper one as long
as five or six upper arm-plates, hut the uppermost of all is not the
lon g est; the upper spines are richly and delicately echinulated, and,
owing to the great encroachment of the side arm-plates on the upper
surface of the arm, the spines of either side come to lie very close to
one another, and soon obscure the arm itself. One small tentacle-,
scale. The lower arm-plates have a concave notch on their adoral
edge, have a short side passing into the short lateral edge, and are
three-sided on their aboral face, so th at they form_ an irregular
hexagon which is broader than long. Owing to the size of the side
arm-plates, the upper arm-plates are lozenge-shaped.
This species has a most elegant appearance, the black hand already
spoken of relieving the whiteness of all the other parts, while a kind
of feathery appearance is given to the arms by the delicate plates
and long glassy spines.
Prince of Wales Channel.
25. Ophiomaza cacaotica.
Lyman, p. 37.
The coloration of these specimens is very far from the chocolate
of Mr. Lyman’s ty p e ; hut three specimens collected in one locality
(Oulf of Suez) are—one chocolate-coloured, one quite light, and one
intermediate. A discussion, however, of the characters of the
variations of this species will be more profitable when onr series is
larger.
Port Molle; Prince of Wales Channel.
1 I
11
!
i ' '
. I
! ’ f
! L ■ !I:
1! . !
I" ;+ ■ If
'