FOSSILS OF NEW SOUTH WALKS. 701 
Its length and height is 5 inches; thickness 6°, L.; apical angle about 100°. The 
specimen is from Harper’s Hill. 
Isocardia 2 J. D. Sowerby, in Mitchell’s Exped. into Australia, vol. i. p. 15, pl. 2, figs. 1, 2. 
Eurydesma cordata, J. Morris, in Strzelecki’s New South Wales, p. 276, pl. 12, the second and 
third figures; also the first ? 
53. Carpium ausTRALE (IM’Coy) Dana.—Oblong, compressed, dilated, semicircular 
in front, diminishing much and prolonged behind, strongly carinate from the beak to the 
infero-anterior margin. Anterior to the carina, the surface a little concave, and finely 
striate longitudinally ; posterior to it, costate, four costee moderately broad, next nine or ten 
much narrower, and the following again broader.—Length 17 inches; height rather less 
than two-thirds the length.—Plate 8, figure 2, valve, natural size, with the beak imperfect. 
Glendon, valley of the Hunter. 
Pleurorhynchus australis, M’Coy, Ann. and Mag. Nat. Hist., vol. xx., p. 300, pl. 16, fig. 4— 
M’Coy mentions Wollongong as a locality; the author did not meet with it there; and from 
the term ‘“ sandy schists” applied to the containing rock, we should suspect Glendon to have 
been the locality of his specimen. 
54, Carpium FEerox (Dana).—Very large ; thick and very strongly costate ; the coste 
unequal, broad, nearly flat and subangular. Anterior (?) muscular impression suborbi- 
cular. Palleal impression excavate, acute and undulate.—Plate 8, fig. 3, view of part of 
inner surface of the extremities of two valves, and cast of exterior in part ; 3 a, 0, different 
views of interior cast of the same, showing muscular and palleal impressions, 
Wollongong Point, District of Illawarra. 
Our specimen of this species is only a portion from one end of the shell, as represented 
in the figures referred to ; of this part, the valves, and an external and internal cast, are 
preserved. The valves, where stoutest, are over half an inch in thickness. The height 
of the specimen could not have been less than 5 inches, and the thickness 33 or 4 inches. 
The coste are very irregular, often subdividing, and are from an eighth to a quarter of an 
inch, or more, in width; they are more or less longitudinally striated. The muscular 
impression is nearly an inch in its horizontal diameter ; and is indistinct in its markings. 
The palleal impression in the cast is a neatly acute raised line, with short undulations, 
(about four to half an inch). The end of the shell is a long, nearly erect curve, indicating 
that the animal was higher than its thickness. 
We have referred this species to the genus Cardium; but we still cannot understand 
how in a Cardium there should be a strong marginal costa, and the other coste nearly 
parallel with it, in a continuous series, In the species of Cardium the coste usually ter- 
minate on the margin; and this is a general truth with respect to bivalves, 
Genus CYPRICARDIA.—Several of the following species have the form of Mytilus 
or Avicula, and one that of Gervillia. But they are also similar in form to species of 
Cypricardia ; and besides, they approach that genus in the very strong anterior muscular 
impression, situated far forward, near the anterior margin. The structure of the shell in 
three species, (the C. arcodes, C. imbricata, and C. acutifrons,) is very beautifully fibrous ; 
the other specimens are external casts. This character removes them from Mytilus, 
while it does not oppose their union with the Cypricardiz. Moreover, the species occur 
with deep-water molluscs, and this was evidently their natural habitat. The character of 
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