481 
Genus— OOBIMTA, L. Agassiz, 1842. 
(Etudea critiquea Moll. Fosa., 3e Livr., p. 262.) 
CoETMTA WiLSONi, Moore, sp., PI. 28, figs. 10 and 11. 
Thracia TFtoni, Moore, Quart. Journ. Geol. Soo., 1870, xxvi., p. 254, t.l4, f. 8. 
Sp. Char. Shell transversely ovate, thin, compressed, especially towards the 
posterior ventral margin, slightly inequivalve. Hinge-line slightly concave anteriorly, 
and the same, or horizontal, on the posterior ; ventral margin rounded j internally the 
upper of the posterior ribs is placed close under the hinge-line, and almost^ parallel to 
it, but the lower hounds the posterior slope, and is oblique. Anterior side shorter 
than the posterior; the latter is somewhat produced, and sub-truncate ; posterior slope 
slight ; diagonal ridge rounded and inconspicuous. TJmbones nearly median, but nearer 
the anterior end. Surface with concentric growth-laminae and striae, all becoming 
stronger on the posterior end. , , i ■ 
Obs. The shell represented in PI. 28. fig. 10, is Mr. Moore’s type, and thw 
figure, of the natural size, may be taken as a sample of the unreliable nature of his 
illustrations of the Queensland fossils generally. It is preserved in the Museuni ot 
the Literary and Philosophical Society of Bath, and I am indebted for the loan of it to 
the kindness of the Committee of that Institution through the Eev. H. H. Winwood, 
M.A. , ^ . , , T 
This fossil has the shell preserved, but in fig. 11 of the same plate is what 1 
believe to be the internal cast of another species. The two grooves under the posterior 
hinge naturally represent shelly ribs on the interior of the valve, and correspond to 
the structure of Agassiz’s Corimya, especially as there is no trace of hinge teeth, or 
other features, which would invalidate the reference, such, for instance, as the 
cartilage pit of Anatina. It is probably Mr. Hudleston’s Thracia primula,* from South 
S txStl l£l 
Mr. Moore mentions the existence of an external ligament, and describes the 
valves as unequal, through the presence of “ a slight sinus towards^ the centre of the 
ventral margin, with a corresponding elevation on the opposite valve.” The possession 
of a ligament by this species would support Stoliczka’s view that Corimya furnished 
with such a mechanism. The inequality of the valves I have not seen. 
Loc. and Sorizon. Amby Eiver and Bungeworgorai Creek (^The late Rev. W. B, 
Clarke') ; Mimni, near Eoma {B. L. Jack). 
Pamily— MACTEID.®. 
Genus— MAOTBA {Linn?), Lamarck, 1799. 
(Mdm. Soc. Hist. Nat. Paris, 1799, p. 85.) 
Mactea teiqonalis, Moore, PL 27, fig. 17. 
t^aotra trigonalis, Moore, Quart. Journ. Geol. Soo., 1872, xxvi., p. 252, t. 14, f. 6. 
Sp. Char. Shell small, thin, trigonal; umbones rather anterior; anterior end 
rounded and rather angular; front margin rounded; the surface is marked by taint 
transverse lines. {Moore?) 
Loo. Hive Eiver Downs {The late Bev. W. B. Clarke). 
2 e 
* Geol. Mag., 1890, vii. (3), p. 245, t. 9, f. 7. 
