4 
195 
Horizon and Localities . — Of the typical specimens,, on which Mr. 
J. Morris estahlished the species, some come from the Eastern Marches and 
Mount lYellington, Tasmania, and others from Elawarra and Eaymond 
Terraco, N. S. Wales. Mr. W. B. Clarke found specimens of it at Mount 
Wingen, and Coyeo on the Page River, at Korinda, Aellalong, and Nowra Hill. 
SpiiiiFER EXSUPERANS, L. G. de Kouinck} 
PL XV, Pig. 1. 
This shell is transverse, suhpyramidal, about one-third broader than 
long, and terminates in a point at each extremity. The dorsal valve is semi- 
elliptical and shallow ; the dorsal ridge is simple, very convex, and broad 
towards its frontal extremity ; the beak is very elevated, slightly recurved, 
and pointed ; the hinge-area is very large and high, and extends across the 
whole breadth of the valve ; the deltoid fissure is broad and its height exceeds 
half the breadth of its base. Tliis fissure is closed in its upper part near the 
beak by a small pseudodeltiuni. Both sides of the surface of the shell are 
ornamented with from fifteen to eighteen radiating, simple folds, rounded 
and separated by shallow furrows. In its internal structure this species is 
rather remarkable, and in no way resembles that of the Syringothyris 
Guspidatus, W. Martin, with whic"' I at first confounded it. Two strong, 
diverging, dental plates occupy the bottom of the ventral valve, by which the 
framework is perfectly consolidated ; between these diverging plates (which 
do not extend beyond half the length of the valve), and immediately below 
their junction, is the central impression of the adductor muscle; this impression, 
in the shape of a lozenge, is longitudinally plicated, and flanked by two rather 
deep cardinal im^u’essions striated lengthways. The rest of the shell shows 
irregular, oblique furrows, probably depending from the vascular process. 
The internal part of the hinge area shows some small rounded pits, not very 
regular either in shaj)e or arrangement. The interior of the dorsal valve is 
unknown to me. 
Dimensions . — The length is about two, and the breadth eight, centi- 
metres ; the terminal angle of the beak is 130° ; the height of the hinge area, 
twenty-one millimetres ; and the breadth of the deltoid fissure, at the base, 
fourteen millimetres. 
' [Syrhujothyris cxsuperans, de Koninck. A. H. Foord, Geol. Mag., 1890, VTI (.3), p. 149, 1.53 ; R. 
Etheridge, Jun., Records Geol. Survey N. S. Wales, 1897, V, Ft. 2, pp. 43-48, t. 6. — W.S.D.] 
2 D 
