Upper Silurian.) PALZONTOLOGY OF VICTORIA. [Mollusea, 
Very common in May Hill sandstone of the hills near porphyry 
dyke near Mount Disappointment (B? 17). 
EXPLANATION OF FIGURES. 
Plate XLVI.—Fig. 2, old individual of wide variety, entering valve, natural size. Fig. 2a, 
same view magnified. Fig. 26, portion of surface of same specimen more highly magnified. 
Fig. 3, long variety, receiving valve, natural size. Fig. 3a, same view magnified. Fig. 3d, 
entering valve of same specimen magnified. Fig. 3c, side view of both valv f same spe- 
cimen magnified. Fig. 4, intermediate variety, entering valve, natural size. Fi , same view 
magnified. Fig. 5, long variety, young individual, entering valve, natural size. §Tig. 5a, same 
view magnified. Fig. 56, view of receiving valve of same specimen magnified. g. 5c, rostral 
view of both valves of same specimen magnified. Fig. 5d, front view of both valves of same 
specimen magnified. 
Prats XLVI., Fia. 6. 
TREMATOSPIRA FORMOSA (Hatz). 
DrscripTion.—Longitudinally ovate, moderately convex, beak of large valve 
pointed, a very narrow mesial sulcus containing two ridges smaller than those of the 
sides; 10 or 11 regular simple sub-angular ridges on each side crossed by a few 
strong imbrications of growth near the margin. Surface coarsely granulo-punctate. 
Length, 4 lines; width, 8°. Apical angle, about 100°, or rather less, 
REFERENCE.—Hall. Pal. N. Y., vol. 3, t. 36, f. 2. 
There seems no difference between the Australian specimens and 
those of the Lower Helderberg shales of Albany. 
Not uncommon in May Hill sandstone of (B® 17) hills west of 
Mount Disappointment. 
EXPLANATION OF FIGURES. 
Plate XLVI.—Fig. 6, specimen of receiving valve, natural size. Fig. 6a,same view magnified. 
Fig. 6b, portion of surface more highly magnified, showing the coarse tubulo-punctate surface. 
Puate XLVI, Fias. 7, 8. 
SPIRIFERA PLICATELLA (Lin.). Var. MACROPLEURA 
(ConraD ). 
(Genus SPIRIFERA (Sow.). (Sub-kingd. Mollusca. Class Palliobranchiata, Order 
Brachiopoda, Fam. Spiriferide.) 
Gen. Char.—Transversely oval or sub-rhomboidal, gibbous, often radiatingly ridged and with 
a mesial ridge on entering valve and corresponding mesial sinus on receiving valve; hinge-line 
usually as long as the shell is wide; cardinal area nearly parallel-sided, of moderate width in 
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