« Shell fragile and elastic, with concealed spire, and either a sutural slit or a posterior “spout”; no distinct anal fasciole; aperture very narrow above, effuse and open below, showing the whole interior from the base. Animal with a quadrate head disk, bilobed behind. No epipodial lobes. » – H. A. Pilsbry: Manual of conchology, structural and systematic ser. 1, vol. 15, Philadelphia 1893, p.351.
 

In this genus, the shells « have an almost straight outer lip, a relatively shallow apical area with the protoconch in the centre of a domed inner whorl, and an apical keel continuing in the reflected inner lip. » – Jensen & Wells: “Sacoglossa (= Ascoglossa) (Mollusca, Opisthobranchia) from southern Western Australia”, The Marine Flora and Fauna of Albany, Western Australia vol.1, Perth 1990.