The whole exterior surface is covered with fine, concentric, imlndcated 
lamellse, easily scaling off. The shell is thin and fragile. I could not see 
the hinge, hut the general form of the shell so perfectly resembles that of the 
Carboniferous Scaldia, of Belgium, that I have little doubt of having 
determined it correctly. 
Dimensions. — The length is thirteen, the breadth twelve, and the 
thickness six, millimetres. 
Delations and Differences. — Of all the species known to me, S. 
Omaliusiana, Byckholt, most resembles S. lamellifera ; but it differs by 
being less depressed, and especially by the folds of its surface not being 
laminated. 
Horizon and Localities . — A single specimen of this species, with 
both valves extended on the same plane (see my figure), was found in a 
greenish-grey sandstone at Harpur’s Hill. 
SANGUINOLITES, McQoy.^ 
Sanguinolites undatus, J. D. Dana. 
PL XVII, Pig 1. 
Dlioladomija {Flatymya) undata, J. D. Dauca, 1849, Greol. Wilkes’ U. S. Explor. Exped., 
p. 687, pi. 2, fig. 11. 
This shell is of medium size, elongated, elliptical, nearly as thick as 
broad, with a straight hinge line, and a regularly curved ventral margin ; the 
anterior margin is rounded, while the posterior is slightly and obliquely 
truncated, and moderately gaping. Its beaks are rather thick, strongly 
recurved upon themselves, close together, and situated towards the anterior 
third of the total length of the valves. The valves are regularly vaulted and 
very deep ; their surface is ornamented with numerous concentric undulations 
of growth ; these undulations are only faintly marked on the internal casts, 
but are more numerous and distinct on the test, which is thin and seldom 
preserved. 
' [Speaking of the Australian Permo-Carboniferous fossils referred to Sanguinolites by de Koninck, Mr. R. 
Etheridge, .Junr., says “ These are not Sanguinolites, as the genus is now restricted.” Several of them he refers 
doubtfully to Meek’s Chcenomya. Geol. and Pal. Q’land., 1892, p. 281. — W.S.D.] 
