■ä: I
This so-called species, also Q. donacina, Lamarck, C. cumingii, A.
Adams, 0. castanea, Eeeve, 0. errones, Eeeve, and O. decipiens,
Eeeve, I believe to be mere variations of one and the same form,
namely 0. Idngicola, Lamarck. The composition of the hinge is the
same in all, and the peculiar colouring of the interior is similar {vide
Eeevo, fig. 16, and Delessert, pi. iv. fig. 1 h). The variation in form
is partly due to age ; for instance, a young Q. decipiens has the form
of donacina, and it is only towards maturity th at the posterior end
becomes markedly produced; and the same observation applies to O.
errones. _ The amount of concentric ribbing is not constant; but all
intermediate forms are met with, from C. castanea and Q. donacina
(type), which have least, to 0. pulchra, which has most, being costate
throughout, except at the posterior extremity. Tho pallial line
in evm-y specimen examined does not appear to be parallel with the
margin of tho valve, but becomes gradually more remote anteriorly,
the space between it and the margin being radiately shallowly
snbsnlcate, seen better in some lights than others. The epidermis
scarcely varies at a ll : in some examples it appears to have lost the
dull bloom which covers others; but this defect is the result of friction,
for a dull specimen in perfect condition is easily rendered
glossy by rncrcly being rubbed with a wet cloth, the bloom disappearing
as it does from fruit under similar circumstances. Judging
from the specimens in the British Museum with reliable localities
attached to them, it appears th at the species ranges from Queensland
on the east side of Australia, along the north coast to Swan Biver on
the west. I find a specimen of the variety cumingii from Port
Curtis and another from Sandy Cape on the north-east coast; var.
pidclira ffiom Port Essington; vars. decipiens and castanea from
Swan Bivcr.
50. Modiola, sp.
Hab. Port Molle.
A single distorted specimen only is before me, remarkably like
the European AI. barhata.
51. Modiola glaberrima.
Hunker ; Eeeve, Conch. Icon. fig. 48.
Hab. Sydney {Hunker') ; Port Jackson {Coppinger and Angas).
52. Modiolaria miranda. (P la te YII. fig. N.)
_ Shell transversely elongate,_ highest at the middle, of pale greenish
tint, varied with a few indistinct light reddish irregular markings,
not glossy, rather strongly radiately ridged at both ends aud very
finely on the central portion of the valves. Whole surface concentrically
striated,^ producing a subgranose appearance upon the cos-
tulæ ; the anterior are about ten in number, the posterior about
twice as many, and produce a denticulate margin to the valves.
Interior slightly iridescent. Umbones small, glossy, not radiately
sculptured like the rest of the sheU. Length 6 miPim., height 3 |,
diam. 3.
Hah. Dundas Straits.
This is a very prettily sculptured species, approaching, as regards
outline, AI. varicosa. I t is, however, quite distinguishable by the
greater coarseness and suhgrannlar character of the radiating anterior
and posterior ridges.
The single specimen described above may not be full-grown ; but
I conjecture it never attains a much larger size.
53. Modiolaria varicosa. (P la te V II. figs. M, M 1.)
Gould, Proc. Bost. Soc. Nat. Hist. 1861, vol. viii. ; Otia Conch, p. 176.
Hah. Port Jackson {Coppinger) ; Sydney {Gould).
This pretty little species was figured by Beeve (Conch. Icon. fig. 83)
as the young of Alodiola strigata, Hanley ; and this must have in duced
Goiild to observe th a t it “ is marked like ’j th at species, for
in reality there is very little resemblance in the painting of the two
shells. The radiating sculpture is faintly indicated in the_ above
figure by means of scratched lines, but these are only noticeable
under a lens.
54. Lithodomus teres.
Modiola teres, Philippi, Ahhild. vol. ii. p. 148, pi. 1. fig. 3.
Lithodomus teres, Beeve, Conch. Icon. fig. 13.
Hah. Pacific Ocean {Phil.)-, Philippine Islands {Cuming); Port
Denison, Queensland {Coppinger).
The anterior perpendicular striæ are rather coarse in this species ;
the raised interstices between them are very conspicuous at the
margin, and gradually become finer as they ascend the valves, sometimes
furcating at one or more of the concentric lines of growth.
The interior is pinkish or bluish, and more or less iridescent.
55. Area navicularis.
Bruguiere; Philippi, Ahhild. vol. ii. pi. 3. fig. 2; Eeeve, Conch. Icon.
fig. 70 ; Wood, Index Test. pi. 9. fig. 5.
Vai°=Arca liiiter, Jonas, Philippi, I. c. fig_. 1. _
Var.=Arca siihquadrangida, Hunker, Philippi, I. c. fig. o.
Var. = Area cumingii^ {MS, in coll. Cuming) \ Adamsj Genera
Moll. ii. p. 533.
Hab. Port Molle, Queensland (Gop^imper); Port Phillip, China,
Cape Capricorn, Amboina {Brit. AIus). _
The varieties respectively called A . linter and A . subquadranguLa
are distinguished only by very variable characters, such as form and
the amount of ligament, which in this group of Arks are of little
value.
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