24 
K. L. Prexdergast. 
MatericK — Aus. Miis. F 38453-38457, 9069, Minilya Biver, North-West 
Division. Wandagee Stage. 
Aus. Mus. P 37580, Vi mile west of shale outcrop. Northern bank. Same- 
locality and horizon. 
Aus. Mils. F 37576, % mile cast of shale outcrop. Northern bank. Same 
locality and horizon. 
Aus. Mus. F 16729, 10749, Irwin River District Fossil Cliff horizon. 
Aus. Mus. F 37565, ^4 mile east of fault, south bank of Minilya River, 
North-West Division. Wandagee Stage. 
Diagnosis . — Linoproductids with non-sinuate pedicle valve, hinge-line' 
equal to greatest width of shell, umbo overhanging hinge-line; ears distinct 
but not prominent. Shell ornamentation of fine striae, becoming swollen 
at regular intervals to give anteriorly directed spines, quincuneially arranged. 
Row of spines along cardinal margin. Visceral disc crossed by concentric 
wrinkles; size and extent of wrinkles variable. 
Brachial valve flat over visceral disc becoming strongly geniculated' 
anteriorly. Short median septum. Ornamentation as on pedicle valve. 
Internal features not known. 
Description . — For description and discussion of this species see Prender- 
gast, 1934, p. 14. 
Linoproductus cancriniformis var. lyoni var. nov. 
PI. iii, figs. 1-2. 
Jfolofypc-. — Aus. Mus. F 36530, 10 chiis. north-west of Giiarrca Pool near- 
Winning Statin, North-West Division. Lyons Stage. 
Topotypes. — Aus. Mus. P 36533, 36535, 36537, 36538, 36540. Same locality 
and horizon. 
Diagnosis . — Shell medium to large, semi-circular outline. Pedicle valve 
evenly convex, not swollen, without median sinus. Hinge-line straight, equals, 
greatest width of shell. Umbo strong, not incurved, not overhanging hinge- 
line. Ears large, fiat, not clearly differentiated from body of shell. Orna- 
mentation as in Linoproductus caneriniformis Tschern. 
Brachial valve and internal structures of pedicle valve not known. 
Description. 
Dimensions. 
36530. 
36531. 
36532. 
Length of hinge-line 
43-7 
34-5 
22*7 
Height 
32-6 
28-0 
21-5 
Curvilinear length of pedicle valve 
41-0 
25*8 
34-2 
The pedicle valve has a semi-circular outline with the greatest Avidth at 
the hinge-line. The longitudinal profile of the shell is a regular cuiwe be- 
coming geniculate near the front; transversely the curve is regular, without 
any median flattening. The ears are large Avith alar angles right angles, 
they are not distinct from the body of the shell. The shell surface is 
covered Avith fine radial striae (10-13 in 10 mm. measured at a distance of 
20 mm. from the umbo) bearing swollen elongated spine-bases arranged in; 
