49 
1X3) 
MOORE-—AUSTRALIAN MESOZOIC GEOLOGY. 
crossed by regular concentric fimbriated strise, which in the inter- 
Spaces are produced beyond the shell. The umbo and auricles are 
wanting, and the shell is otherwise imperfect. 
Loc. Wollumbilla. 
26. PERNA GIGANTERA, sp. n. 
Shell very large, measuring 63 inches broad by 524 inches in 
length, inequilateral, flattened ; umbones depressed and rather pro- 
duced ; anterior byssal area rounded, hinge-line rather oblique, ex- 
tending one-third the width of the shell; posterior end oblique, 
rounued and folding towards the ventral margin, which with the 
anterior end is rounded. 
It is in a sandy boulder somewhat resembling green sand, which 
under the lens is seen toe contain black-looking chloritic grains. 
The boulder contains Lingula ovalis and Mytilus, which show the 
Perna to be of the same age as the Wollumbilla scries. 
It is the only example known, and is from Wollumbilla. 
27. ARCA PLICATA, sp.n. Pl. XII. fig. 6. 
Shell small, quadrate, left valve convex ; hinge-area wing-like and 
extended, angular; posterior margin truncated; surface with a few 
wide radiating striz, several of the more distinct of which are on 
the angulated portion of the posterior end. 
Only one example is known. It is from Wollumbilla, and the 
block also contains many Jingule and small Pectens. 
28. Arca PRELONGA, Sp.n. Pl. XIV. fig. 7. 
Shell transverse, inequilateral; umbones rather close, anterior ; 
hinge-line long, with numerous close-set teeth; posterior side ex- 
tended and slightly angulated, with a depressed keel crossing from 
the umbo to the posterior ventral margin. The specimen does not 
exhibit the finer ornamentation of the test. 
It is from Wollumbilla. 
29, ASTARTE APICALIS, sp.n. Pl. XIII. fig. 11. 
Shell small, trigonal, flattened; umbones very acute, almost 
mesial; anterior and posterior margins oblique; ventral margin 
straight ; surface ornamented with distant raised and straight trans- 
verse lines of growth. 
Several specimens of this species are attached to one of the 
blocks from Western Australia. It is associated with Zrigonia 
Moorei, Lyc., Cucullea, &e., and is evidently to be referred to the 
Inferior Oolite. 
Loc. The Greenough district. 
30. Astarte Ciirroni, sp.n. Pl. XIII. fig. 10. 
Shell thick, ovately trigonal, flattened, inequilateral ; umbones 
acute, small, anterior ; anterior side short; posterior end the longest, 
yery oblique, and produced towards the ventral margin, which is 
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