Ws 
UNRECORDED GENERA OF THE OLDER TERTIARY FAUNA. 191 
limited surface of the dorsal region, has the umbo quite free and 
resembles a cuneiform M/yadora ornamented with sharp concentric 
ridges ; the rest of the unattached surface has broadish flat con- 
centric folds intricately wrinkled. Left valve slightly convex 
with wrinkled corrugations, antero-posterior and umbo-ventral 
diameters approximately equal from 17 to 20 mm. 
Class PALLIOBRANCHIATA. 
Genus Crania. 
CRANIA QUADRANGULARIS, spec. nov., Pl. xi, fig. 12. 
Attached valve unknown. Free valve with a transversely 
oblong outline, test very thick; the hinge-line is straight with 
sharply rounded angles, anterior and posterior margins nearly 
straight, ventral margin slightly outwardly curved, greatest width 
medially in a transverse direction ; apex blunt and tumidly elevated 
varying in position from nearly central to about the dorsal one- 
third; surface with subimbricating growth-folds and fine close 
radial striz; interior with the ventrally situated scars rhomboid 
and separated by a stout septal ridge. Dimensions:—(Ex. 1) 
diameters 15 and 10, height 3:25; (Ex. 2) diameters 14:75 and 
12, height 4 mm. 
’ Locality:—Eocene: Waurn Ponds near Geelong (Mr. Mulder). 
The more or less regular convexity of the free valve separates 
it from that of all living species which are distinguished by an 
apiculate vertex ; however, it is only with C. anomala that I have 
made comparison with actual specimens. The tumidly convex valve 
and the septal ridge in the interior may prove to be distinctive 
characters. 
Class ECHINODERMATA. 
Genus Celopleurus. 
This name replaces my Murravechinus; the species represented 
has been described by Gregory as C. paucituberculatus. 
Genus Paradoxechinus. 
The two species quoted under Temnechinus belong here and are 
varieties of one species, P. novus, Laube. 
