Pteropods with convex ventral and dorsal parts. Sculpture: radial on dorsal side, transverse on ventral side.
 

« Ventral and dorsal shell parts only connected to each other in basal part, separated by lateral slits, dorsal lip overhanging aperture, apertural margins not thickened, closing mechanisms present on both sides between aperture and lateral slit; apical spine with protoconch curved dorsally, pointed, with transverse microornament; sometimes shed, opening closed by septum. » – Janssen, Bush & Bednaršek: “The shelled pteropods of the northeast Pacific Ocean (Mollusca: Heterobranchia, Pteropoda)”, Zoosymposia vol.13, Auckland 2019, p.327.
 

« Among extant euthecosomatous gastropods, species of the genus Cuvierina are well-characterised by a number of shell features, in particular the straight, cylindrical to more or less inflated shell form and the proximal aperture of reniform or rounded triangular shape. In(near-)adult shells a semispherical, more or less obliquely situated septum is formed, after which the apical shell part (larval shell) is shed. » – A. W. Janssen: “Development of Cuvierinidae (Mollusca, Euthecosomata, Cavolinioidea) during the Cainozoic: a non-cladistic approach with a re-interpretation of Recent taxa”, Basteria 69, 2005, p.26. The dorsal apertural margin is slightly higher than the ventral one.
 

Close to the shell of Cavolinia, but without transverse striations, more compressed laterally, and featured with a rather long posterior spine, while the lateral ones are shorter than in Cavolinia.
 

« The younger shell which has an oval protoconch is deciduous. Main features: globular hyaline or brown teloconch, no lateral spines, apex closed by a septum. There are three to five variably dorso-longitudinal ribs; the ventral face has transversal striae. The peristome has a thickened dorsal lip with transversal striae […]. Near the lateral fringes of the pallial cavity there is a characteristic region containing vacuolised cells. » – J. Rampal: “Euthecosomata (Mollusca: Gastropoda: Thecosomata). A taxonomic review”, Bollettino Malacologico vol. LV, Milano 2019, p.165.