What is "trissexodontidae"

Trissexodontidae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Helicoidea (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005).

This family has no subfamilies. The family Trissexodontidae was separated out from the families Hygromiidae and Helicodontidae, and some authors still classify these species within those families.