Upper Silurian. ] PALAONTOLOGY OF VICTORIA. [ Mollusca. 
Descrrprion.—Transversely oval, beaks very small, both valves moderately and 
nearly equally convex, most so at about one-third of the length from the beaks; a 
very slight narrow mesial sulcus in each valve, slightly indenting the front margin ; 
sides semi-elliptically rounded ; surface with a few strong imbrications of growth 
marked under the lens, with coarse tubulo-punctate longitudinal interrupted striz ; 
width, 5 lines; proportional length, 7%3,; depth of both valves, -35. 
This species is almost identical with the Wenlock shale Aérypa 
compressa (Sow.) of Wales in shape, and with the Nucleospira 
ventricosa (Hall) of the Lower Helderberg beds (= Wenlock) of 
New York, but is more compressed than the latter and rather wider 
and more regularly transversely oval than either. The remains or 
indications of coarse punctation and longitudinal streaky remains 
apparently of minute tubular spines, can be seen on the casts with 
alens. The WV. piswm of the English Wenlock shale is longer and 
much more convex. 
Common in May Hill sandstone (B’ 17) of hills west of Mount 
Disappointment. 
EXPLANATION OF FIGURES. 
Plate XLVII.—Fig. 7, view of entering valve, natural size. Fig. 7a, rostral view, showing 
the two valves of same specimen, magnified. Fig. 75, entering valve of same specimen magnified. 
Fig. 7c, receiving valve of same specimen, magnified, showing chamber in beak. Fig. 7d, side 
view of same specimen, natural size. Fig. 8, broader variety, receiving valve, natural size. 
Fig. 8a, same view magnified, showing chamber in beak and cardinal teeth. Fig. 8b, portion 
of surface of same specimen magnified to show the tubulo-punctate structure. 
PuatEe XLVII., Frias. 9, 10, 11, 12. 
PENTAMERUS AUSTRALIS (McCoy). 
{Genus PENTAMERUS (Sow.). (Sub-kingd. Mollusca, Class Palliobranchiata. Order 
Brachiopoda, Fam. Rhynchonellide.) 
Gen. Char.—Shell ovate, convex, beaks incurved, receiving valve largest, with or without 
mesial fold, with or without hinge-line and cardinal area; a deep triangular pit under the beak 
of receiving valve into which the beak of the entering valve is strongly incurved. Internally 
the receiving valve has one bipartite central septum divaricating to form the walls of the 
external triangular opening, enclosing a triangular space much smaller than the two lateral 
ones ; in the entering valve there are two sub-parallel septa, one on each side of the middle, to 
which the socket walls converge, sometimes defining a rostral chamber like that of the receiving 
valve. Texture of shell fibrous. Paleozoic only. ] 
Descriprion.—Longitudinally snb-ovate, moderately convex, widest a little 
behind the middle, narrower in front, with an indistinct broad slight mesial elevation 
of the middle of the entering valve. Surface nearly smooth, with a few concentric 
lines of growth and a few faint irregular longitudinal furrows. Cardinal area 
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