Eatoniella fossa has a solid, smooth shell, with a groove between the inner lip and the molluscs body whorl. The shells' colour varied between brownish-yellow to white, with an occasional dark band. The holotype of the species measured 1.9mm by 1.2mm.[2]
This species is easily distinguished by the channel between the aperture and the body whorl of the mollusc.[2]
^ abBieler R, Bouchet P, Gofas S, Marshall B, Rosenberg G, La Perna R, Neubauer TA, Sartori AF, Schneider S, Vos C, ter Poorten JJ, Taylor J, Dijkstra H, Finn J, Bank R, Neubert E, Moretzsohn F, Faber M, Houart R, Picton B, Garcia-Alvarez O, eds. (2022). "Eatoniella fossa Ponder, 1965". MolluscaBase. World Register of Marine Species. Retrieved 15 November 2022.