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and bifid, and two in the left, of which the anterior is the largCT and
bifid. A single lateral tooth occurs in the right valve on each side
not far from the cardinals, with a groove between them and the
margin. Left valve with a slight tooth-like projection on the imr-
gin on each side fitting into the grooves in the other valve, ih e
pallial sinus is large and deep. Internal cartilage minute, narrow,
oblique, posterior to tho cardinal teeth. External ligament small.
The largest specimen measures 13 millim. by 9g. T. alba of Wood
is somewhat like this species, but is more acute posteriorly, the
detail of its dentition is different, and the cartilage larger.
27. Mactra eximia.
(Deshayes) ; Reeve, Conch. Icon. fig. 31 (rayed variety).
Hah. Port Denison, Q u e e n s la n d (Go+pmqer); Port Curtis, Moretón
Pay {coll. Gaming) ; N.E. coast of Australia {Brit. Mus.).
There are altogether eight specimens of this species in the Museum,
three of them being ornamented with numerous reddish rays, and
the remaining five uniformly white beneath the greyish and yellowish
epidermis.
28. Mactra producta, var.
Spisula producta, Angas, Proc. Zool. Soc. 1867, p. 909, pi. 44. fig. 7.
Hab. Port Jackson {Angas and Coppinger).
The three shells dredged by Dr. Coppinger are probably a variety
of this species. They are all small, apparently immature, and differ
from the types presented to the Museum by Mr. Angas in being
less produced posteriorly. They are proportionally longer from the
umbones to the ventral margin, which exhibits a very faint incurvation
near the hinder extremity, and the posterior dorsal slope is a
trifie more arcuate.
29. Mactra (Oxyperas) coppingeri. ( P l a t e Y II. figs. D-D 2.)
Shell transversely elongate, triangular, a little inequilateral,
rather compressed, thinnish, narrowly gaping posteriorly, smooth
towards the beaks, concentrically plicately ridged elsewhere, white,
covered with a pale yellowish epidermis, spotted somewhat sparsely
throimhout with brownish dots, and ornamented on the dorsal areas
with cross lines of a deeper brown, and with a large patch of the
same colour on the hinder slope of each valve. Umbones moderately
acute, not large, inclining towards and situated a trifie in advance
of the centre. Lunule sunken, not circumscribed by acute edges,
extending more than halfway down the anterior slope. Posterior
area as deep as the lunule and a trifle longer, smoothish, not much
affected by the terminations of the concentric ridges. Two lateral
teeth on each side in the right valve, separated by a deep groove
quite approximated to the cardinal teeth in front and the cartilage-
pit behind. The latter is large, deep, and located posterior to the
beak. The cardinal tooth is small, insignificant, hounds the ligament,
and has a cross piece above it immediately beneath the apex of the
umbo. In the left valve, the single lateral tooth on each side is
elongate, narrow, and erect. Only one cardinal tooth (unless the
front raised edge of the ligamental fossa be considered a tooth), which
is elongate, but little raised, situated between tho pit and edge of
the lunule. Muscular scars pyriform, the front one elongate, the
posterior more rounded. Pallial sinus extending halfway across the
valves, sharply rounded at the end. A second sinuation within
the other, and consequently shorter and less acutely curved, is a
remarkable feature in both valves of the single perfect shell before
m e ; in a separate valve this is not noticeable, hut may have been
obliterated, as the specimen is somewhat sea-worn. The inner surface
of this species is glossy and radiately substriated, one impressed
ray from the umbones to the end of the mantle-sinus being especially
conspicuous.' Length 3 6 | millim., height 24, diameter 12.
Hah. Thursday "island, Torres Straits, 4 -6 fms.
This very interesting species bears a rather close relationship
to Alactra triangularis of Lamarck; it is, however, quite distinct.
I t is a trifle shorter, less angular, not so strongly concentrically
costate, has an excavated lunule and a sunken area not defined
by carinate edges, and the dorsal margins not prominent, forming a
keel on each side ; the timbones as in M. triangularis. AI. aspersa,
SoAverhy, is a more finely scnlptnred shell, more rounded posteriorly,
with a shallower lunule and a narrower dorsal area. The palliat
sinus in the present species reaches halfway across the valve, ivhilst
in M. aspersa it has a further extension and lacks the duplex feature
described previously.
30. Mactrinnla angulifera.
Mactra angulifera, Deshayes, Proc. Zool. Soc. 1854, p. 70; Reeve,
Conch. Icon. fig. 83.
Hab. Island of Ticao, Philippine Islands {Cuming); Port Curtis
( Coppinger).
Pehind the conspicuous keel which marks off the posterior area,
about midway between it and the margin, there are one or two
minor ridges. In the Cumingian collection there is a second
specimen, somewhat larger than th at figured by Reeve, having a
length of 32 millim. and a width of 47.
31. Cardium reevianum.
Dunher, Novitates Conch, p. 22, pi. 6. figs. 6, 7, 8.
Hab. Port Darwin, 8 -12 fms., bottom mud and sand {Coppinger);
Port Essington {Alus. Cuming).
Cardium vertebratum, Jonas (Zeitschr. für Malak. 1844, p. 33),
from West Australia, is apparently closely related to the present species.
32. Cardium hystrix.
Reeve, Conch. Icon. figs. 40 a, 5 ; Römer, Conch.-Cah. p. 112.
Hab. Corrigidor, Philippines (Cuming); Flinders and Clairmont
Islands, N.E. Australia (Coppinger).
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