Complex sentence: The unique features of the lower lip generated umbilical callus and deep, long, exhalent slit on the upper side along with the generally smooth form set this genus, and family, apart from other Pleuromomaracean gastropods.
Split into simpler sentences: The unique features of the lower lip generate an umbilical callus and deep, long, exhalent slit on the upper side along with the generally smooth form. They set this genus, and family, apart from other Pleuromomaracean gastropods.