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. The distribution of Trissexodontidae includes the Iberian peninsula, northwest Africa, Azores, Canary Islands, Madeira and Cape Verde. Genera within the family Trissexodontidae include:  Shells of species in the family Trissexodontidae are flat and regularly ribbed. The periostracum of the shell surface has no hairs. A description of the reproductive system was summarized by Prieto et al. (1993). In this family, the number of haploid chromosomes is known only for the genus "Oestophora" (n=30).