•I. Ophiopinax stollatiis. ( I ’ l.vn.: VI I I . lig. (1,)
I V c t i n u v a s t o l h i t i i , l.i/inaii, IW/. Lis/, p. ;{.
Disk sonu'what pentagonal, not pnllod, witli a centrai rosi'Mo of
plates varying a good deal in the extent to wliieli it. ia woll dellned,
and oeeupving about lialt' tho nppm- aurt'aeo : in aonio oasea a, eenti-a.l
plato and two not vory regular eireb'ta of varionaly ai/,(al iiladoa of
invgular form ean bo inado out. The inlerradiaraeriea of pla.tea,
whieh extend from tho roaotto to tlu> edgo of tho diak, a.ro at,out,or
and inoro prominent than the radial amaes ; tlu'y are eompoaial of
threo or four plafoa varying in aizo and form, ami aoinotimea jmired
at tho margiii of tlio diak; tho larger median have anmller plates on
either aide. The radiaj, aeries may, for its unilividc'd iiortion, ho
formed by a single plate, hut, as a more general riili', there are
three ; there are no smaller marginal ])lates. The hifureated hand
Avhioh emhraees tho base of tlio arm has usually tliree jiieees on
oitUor half. Just below the margin of tho disk there is a iironiinont
plate, wlneli is placed interradially ; iu shape this is irri'gnlarly
eordiform ; above, on either side, it is hounded by a comjn-ossed or
diamond-shaped plate : between it and the montli-phito there is a
pair of smaller plates and several still smaller plates intcrvoning ;
on the side there is an elongated plate, A\ i(h tv\ o smaller ones, lying
along the edge of tho genital slit. Tlie radial shields aro largo and
triangular, and till np all the space on tho disk between the radial
and interradial plates whieh is not oeeupied by the rosette.
The inner inouth-sliields have a straight outor edge, the sides are
at first straight, and then bending inwards meet one another at a
more or loss acute angle ; they are longer than b ro ad ; tho space
between them and the edges of the mouth is rather loosely g ran u la r;
the outer mouth-shields are about as broad as long, and have a
slightly convex outer edge : tlie nmbo is well marked, and that
shield IS not divided ; the side mouth-shields are well developed,
and are separated from the genital slits by a small granulated patch!
Seven mouth-papilla?, the three innermost small, the innermost
smallest; the next three large, increasing in size from wdthin outwards
; the outennost again small.
The arms begin to narrow immediately after leaving tho disk
and become very delicate at their free ends ; in a well-developed
specimen, in which the disk measures 17 millim. in diameter, they
are 70 milhm. long, 5 millim. wide, and 4-5 millim. high at their
insertion into the disk. Upper surface carinated ; upper arm-plates
about three times as wide as they are long, but, owing to the invasion
of the side arm-plates, the aboral is longer than the adoral edge;
both these edges are straight. ’
There is a pair of pores between the first and second lower arm-
plates : the lower, like the upper, arm-plates have their aboral longer
than their adoral edges, and this, as on the upper surface, is due to
the encroachments of the side arm-plates, and is more strongly
marked near to, than far from, the disk. None of the edges of these
])lal,e,s ai'c curved ; the pintos thoinsclvcs arc at first broader thnf)
long, hnl, (hiring their gradual diininntion in size tlioy tiavo at one
timo their aboral edge e(|iial to tlieir longitudinal, ax is; still further
out they are longer than broad. Alanit six,sh()rt, pO(jrly dev()!()p(;d
spines aro feiind on eaeh of the side arni-plat(!s near ihe disk, of
whieh th(i hu'gest are median in position ; tliey diniinisli in nnniber
a,nd size as they ajipreach the line end of the arm. 'l'w(> small ten-
1,ucie-seahss.
IJpjier snrlace (in alcohol j dark yellow, with spots or patehes of
brown ; tho whole of the actinal surface pale ilcsh-eolour. yUthough,
as a rule, flirce coiisccuilvc sogrnenis are coloured by a darker transverse
patch, there may he only two, or there may he four so ornamented,
and, as Irrcgularil ics, one or moro than four; but ihe coloration
always extends on to the sid(;s of the arm, though it never
jiasHos on to t,hc lower surlaco. Or the whoh; may he very many
shades darker, and then tho darkest parts arc not c,specially remarkable
; this last mode of coloration appears to he by far the most
common.
Port Molle, Q,uocnsland, 14 fms., rock ; and I’ort Ucnisori,
3 -4 fms.
In some examples, which are very much smaller, from Torres Straits
the radial shields arc oviform, the upper arrn-platcs are not nearly
so wide nor so distinctly carinatcd ; the central rosette may he only
barely indicated, though the central plate is very distinct ; the plates
of the interradial series have no small marginal secondary plates.
The side arm-plates at the base of the arm are proportionately much
largor, and in consecjucnce diminish the breadth of the lower as well
as of tho upper arm-plates. Striking as is the difierence in effect
produced by these differences in character, they are, I think, only
to he ascribed to age.
5. Ophiopeza conjnngens.
This species seems to strengthen the opinion, more than once expressed
by Mr. Lyman, th at the genera Ophiopeza and Pectinura are
l?arely to be distinguished. Without a divided mouth-shield, it has
the arms not rounded, as in 0. fa lla x , but keeled above, as is so often
the case in Pectinura.
Most closely allied to 0. fa lla x, it may be distinguished by the
somewhat coarser granulation of its disk, the smaller number of
month-papillse, and the broadened upper arm-plates.
Disk pentagonal, fiattened, 17'5 millim. diam. in one example,
completely covered by a dehcate and regular granulation (of about
twenty grannies to 1 millim.), the underlying scales not large ; the
radial shields, in jserfect specimens, only indicated by depressions.
Mouth-shields not divided, wider than long, with a wide convex
adoral edge, straighter sides, aud a barely convex aboral margin.
Side mouth-shielàs small; the space between the mouth-shield and
the edge of the jaws is marked by a granulation, much coarser than
th a t which obtains elsewhere on the disk. Mouth-papilla seven.
i'M I ' !