42 
J. R. RICHARDSON 
margin) and were referred to Malleia portlan- 
dica by Richardson (1973b). The above descrip¬ 
tion of the species is based on specimens col¬ 
lected in the Mannum Formation. 
M. lunata is smaller in size than the New Zeal¬ 
and species. The largest specimen of M, lunata is 
7.2 mm in length; the largest specimen of 
M. browni from the Museum of Victoria’s col¬ 
lection is 13.3 mm. M. lunata resembles M. clif- 
denensis in beak and cardinal margin, both of 
which are shorter than in M, browni. The hinge 
platform of M, lunata differs from that of New 
Zealand species in its greater width and in the 
socket ridges, which are less strongly convergent 
and project beyond the margin of the valve for 
approximately half their lengths. 
Pilkena gen. nov. 
Name. From the Aboriginal pilkena (different). 
Gender feminine. 
Type species. Pilkena compressa sp. nov. from the Olig- 
ocene of Australia. 
Diagnosis. Sulcate. Beak nearly straight, beak 
ridges sharp; symphytium with low median 
ridge; cardinal margin slightly curved. Hinge 
platform with posterior pits for attachment of 
dorsal adjustor muscles. Loop long, reflected, 
without septal connecting bands. 
Comments. The hinge platform of Pilkena is 
similar to that of Anakinetica in the absence of a 
hinge trough and the presence of posterior pits 
for attachment of the dorsal adjustor muscles. 
Pilkena is distinguished from Anakinetica by the 
more advanced loop and by the position of the 
hinge platform relative to the valve surface. The 
hinge platform of Pilkena does not extend be¬ 
yond the margin of the dorsal valve, so that the 
tip of the dorsal umbo is visible. In addition, the 
posterior surface of the cardinal process is 
steeply inclined, and consequently both the 
posterior surface and the posterior pits face pos- 
teroventrally rather than ventrally as in Anaki¬ 
netica. These features indicate that substrate 
relationships would differ in some respect from 
Anakinetica. 
Pilkena compressa sp. nov. 
Fig. 6A-F 
Name. From the Latin compressus (compressed). 
Type material . Holotype NMV P3629 and paratypes 
NMV P3627-P3633, P134221 from the Gellibrand 
Marl (Janjukian, Upper Oligocene), 1.6 km west of 
Sherbrooke River, near Port Campbell, Victoria. 
Additional locality. Jan Juc Formation (Janjukian): 
Bird Rock Cliffs, Torquay, Victoria. 
Measurements. (In mm.) 
Specimen 
Total 
length 
Dorsal 
valve 
length 
Breadth Depth 
NMV P3629 
27.2 
22.4 
20.1 
9.9 
NMV P3627 
28.6 
24.3 
22.6 
9.8 
NMV P3631 
27.3 
23.0 
20.4 
10.3 
NMV P3632 
25.2 
21.8 
20.0 
9.8 
NMV P3628 
20.8 
18.2 
14.9 
7.2 
Description. Outline ovate, shallowly biconvex, 
ventral valve carinate, dorsal valve sulcate. 
Symphytium flat with median ridge. Cardinal 
.platform outline triangular with broad anterior 
base narrowing to posterior apex; central 
rounded area (presumed anterior surface of car¬ 
dinal process) bordered laterally by socket 
ridges, posterolaterally by pits and posteriorly 
by posterior surface of cardinal process. Median 
septum short, thick, with blade-like ventral 
edge, without traces of connecting bands. Teeth 
triangular, base almost flush with edge of valve, 
walls not excessively thickened. 
Aliquantula gen. nov. 
Name. From Latin aliquantnlus (small), in reference to 
the foramen. 
Type species. Waldheimiaf?) insolita Tate, 1880 from 
the Eocene of Australia. 
Diagnosis. Weakly sulcate. Beak suberect, fora¬ 
men small; beak ridges sharp; cardinal margin 
curved. Hinge platform with small posterior 
hinge trough; swollen crural bases fused or 
almost fused medially; socket ridges not projec¬ 
ting beyond umbo; cardinal process small, dis¬ 
crete. Loop without septal connecting bands. 
Fig. 6. A-F, Pilkena compressa sp. nov. A, paratype NMV P3630, dorsal interior, x 2.5. B-D, F, holotype NMV 
P3629, dorsal, lateral, ventral and anterior (ventral valve uppermost) views, x 1.8. E, paratype NMV P3633, 
ventral interior, x 1.5. G-L .Aliquantula insolita (Tate, 1880). G, NMV P134775, dorsal interior,x2.3.H,I,K.L. 
NMV PI34774, anterior (ventral valve uppermost), dorsal, lateral and ventral views, x 1.3. J, NMVP134776, 
ventral interior, x 2.3. 
