Membranilarnax angustivela Deflandre and Cookson, 1955

Now Membranilarnacia. Originally Membranilarnax, subsequently Samlandia, thirdly (and now) Membranilarnacia.
Holotype: Deflandre and Cookson, 1955, pl.7, fig.4; McMinn, 1988, fig.8C
Locus typicus: Birregurra bore No. 1, Victoria, Australia
Stratum typicum: Eocene

Original diagnosis: Deflandre and Cookson, 1955, p.290
Shell ellipsoidal or almost globular, with a rather thick membrane enveloped in a 2nd delicate membrane that is supported by short processes. These processes are either simple or more often grouped so as to form twisted lamellae which have a worm-like appearance in surface view. External outline irregularly wavy.
Dimensions: Holotype: shell 54 by 41 Ám, overall 67 by 54 Ám, height c. 5 Ám. Range: shell alone 41-59 Ám, overall diameter 51-72 Ám.

Affinities (annotated):
Deflandre and Cookson, 1955, p.290: This species . . . differs very clearly from the known species, particularly in the short distance that separates the outer veil from the true shell membrane.