254 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 
49. Myacrtes pranvs, sp. n. PI. XII. fig. 10. 
Shell thin, ovately elongated; umbones rather anterior, depressed, 
close; anterior margin attenuated ; posterior side most convex, with 
an obtuse slope to a moderately rounded margin; inferior margin 
rounded ; the dorsal surface possesses transverse interrupted lines of 
growth, with, in the interspaces, numerous fine concentric strie. 
From Wollumbilla; only one example is known. 
50. Nucuza Coorrri, sp. n. Pl. XII. fig. 8. 
Shell trigonal, very convex; umbones rather anterior, widely 
separated; anterior side angular, posterior side rather produced and 
attenuated ; ventral margin rounded. 
This shell, for a Nucula, attains considerable size. It is named 
after Sir Daniel Cooper, Bart., late Speaker of the Sydney House of 
Assembly. 
It is from Wollumbilla. 
51. Nucuna truncata, sp. n. Pl. XII. fig. 9. 
Shell triangular; umbones anterior, compressed; anterior side 
very truncated; dorsal margin rounded; hinge-line with about 
seven large teeth on the posterior side of the umbo, and with four or 
five on the anterior side. 
Only a single specimen of this shell occurs. It is readily distin- 
guished from JV. Cooperi by its more compressed form and truncated 
margin. 
Loc. Wollumbilla. 
52. Turacta Witsont, sp.n. Pl. XIV. fig. 8. 
Shell thin, transversely ovate, slightly inequivalve, compressed ; 
umbones obtuse, anterior ; anterior side short and roundly truncated, 
posterior side rounded and angular ; ligament external, anterior to 
the umbones; dorsal surface covered with very fine irregular wavy 
lines of growth, which become oblique on the posterior margin. 
The right valve possesses a slight sinus towards the centre of the 
ventral margin, with a corresponding elevation on the opposite valve. 
Two specimens of this shell have been found. Breadth 3 inches, 
height 23 inches. 
One is from the Amby river, the other from the Bungeeworgorai 
creek, It is named after J. R. Wilson, Esq., of Bungeeworgorai. 
53. TANCREDIA PLANA, sp.n. Pl. XIIT. fig. 13. 
Shell thin, smooth, flattened, transversely ovate, rather inequi- 
valve; anterior side rounded: posterior margin oblique ; surface of 
the shell covered by very fine transverse striations. 
The matrix contains portions of Avicula &e. 
Only one example is known. It is from Blythesdale, fifteen miles 
from Wollumbilla. 
54. Triconta Moore, Lycett, sp. n.. Pl. XIV. figs. 9 & 10. 
[Allied to 7, costata, but has the general figure more ovate and 
