31 
comparatively small, tlattenecl, and apparently rectangular. Morris speaks 
of fifteen rounded costae, Init the costae range up to twenty-five, all simple, 
widely separated, prominent and depressed convex ; the intercostal spaces are 
equally wide in easts, and concave. Tlie Aidiole, both costae and intercostal 
spaces, are traversed by siq)plementary, fine, very numerous radii, so regular 
that they cannot be described as rendering the costae fasciculate. Morris 
says these radii are granular ; those of one of our own specimens may be 
so, l)ut the state of preservation is not sufficiently clear to enable us to 
unquestionably corroborate this. lie also states that the “ furrows ” are 
each divided by a fine ridge, but these are indistinguishable from the 
other radii. The hinge-plates are linear, although well-marked, and the 
chondrophores longitudinally deltoid. 
In two specimens (PI. YIII, Figs. 2 and 3) that we cannot otherwise 
distinguish from this species, a posterior obliquity is to 1)e noticed, but we do 
not consider this alone as invalidating a reference of them to D. Fitloni. 
Localities and Horizons. — Fapto ( C. Cullen) ; Dagworth, IVest 
Maitland (./. Waterhouse). — Permo-Carboniferous — Upper Marine Series. 
Ravensfield (./. JJ'aterhouse, T. IF. H. David, C. Cullen) ; Harper’s Hill 
{T. W. E. David). — Permo-Carboniferous— Lower Marine Series. 
Collections. — Mining and Geological Museum, and Australian 
Museum. 
Heltopecten wingenexsis, sp. nov. 
(Plate XrV, Figs. 2-4.) 
Specific Characters. — Shell (cast) sub-oblong and slightly oblique 
towards the anterior; length exceeding the Avidth ; \mlves plano-convex; 
cardinal margins less than the Avidth of the valves. Left valve convex, Avith 
tlie lateral and A^entral margins rounded, the anterior lateral above slightly 
emarginate, below someAvhat produced ; umbo pointed ; anterior auricle 
flattened, apparently rectangular; posterior auriele not larger than the anterior, 
flattened and pointed, its outer edge emarginate. Right valve flat ; umbo 
inconspicuous ; anterior auricle flat, rectangular, divided off by a deep sulcus. 
Sculpture of the left Amlve consisting of from eight to ten strong, rounded, 
primary costaA, Avith a smaller seeondary ril) betAveen each pair of the former; 
in the right valve are numerous fine close riblets, apparently of one order. 
Hinge-plates narroAV, Avitb a semicircular chondrophore on each. 
F 
