MOORE—AUSTRALIAN MESOZOIC GEOLOGY. 247 
ing. Surface of the shell with broadish radiating longitudinal striae, 
which appear to bifurcate towards the umbo; in the interspaces 
these are seen to be crossed by fine concentric lines of growth. 
The shell is slightly produced towards the posterior margin. Small 
valve not known. 
The above species, as well as some other of the Australian forms, 
appear to be related to the group of which A. braamburiensis may 
be taken as a type. 
It was obtained from near Mount Corby. 
16. Avicuna stmpiEx, sp.n. Pl. XI. fig. 3. 
Shell small, very inequilateral; hinge-line straight; posterior 
auricle very extended, anterior auricle small; left valve convex, 
thickening at the centre, from which proceed seven or eight radiating 
cost ; right valve flattened, without coste. There are also fine 
concentric lines crossing the shell. 
The species is not unlike the young form of A. costata; but the 
posterior auricle is much more produced than in that shell. 
Loc. Wollumbilla. 
17. AvicuULA mQuALis, sp.n. Pl. XI. fig. 4. 
Shell very small, smooth, convex, inequilateral; auricles nearly 
equal; surface with very faint concentric lines of growth. 
Only a single example of the left valve is known. In form it re- 
sembles some of the Aviculidee of the Permian series. 
Loc. Wollumbilla. 
18. AvicuLA, sp. 
Shell very inequilateral ; posterior auricle lengthened, small valve 
flattened ; shell-structure smooth, surface with about 24 fine costze 
radiating from the umbo. On the anterior side the shell possesses a 
large notch for the passage of the byssus. Only a portion of the 
small valve is known. 
Loc. Wollumbilla. 
19. AvicuLA sussTRIaTa, sp. n. Pl. XI. fig. 6. 
Shell small, inequilateral, convex; anterior auricle very small, 
posterior auricle much extended ; anterior margin and front of the 
shell rounding. ‘lhe surface has about 13 spreading longitudinal 
coste, crossed by faint concentric strie. The small valve is not 
exposed. 
Loc. Wollumbilla. 
20. Lima Gorponn, sp.n. Pl. XII. fig. 4. 
Shell ovately oblong, inequilateral, oblique, thin, with about 
15-17 rounded cost, which become obsolete on the posterior side, 
and with many concentric close-set but distinct lines of growth ; 
hinge-line narrow and straight, posterior side rounded, anterior 
oblique; ventral margin rounded. 
Only one good example of this shell has been sent over; but 
VOL, XXVI,—PART I, s 
