Bulla pellucida Brown, 1827 Retusa truncatula is a species of very small head-shield sea snail or barrel-bubble snail, a marine gastropod mollusc in the family Retusidae[1] The subspecies Retusa truncatula var.

mammilata: is a synonym of Retusa mammillata (Philippi, 1836) The shell is minute with a flattened spire and longitudinal striations.

[2] This species occurs in South Africa, from False Bay to Durban in shallow estuaries.

[2] This small sea snail lives from the intertidal zone to just below the low water mark.

It burrows in the mud or sand of tidal marshes, and feeds on foraminiferans.