title: Trissexodontidae
text: # 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.
  
  ## Distribution
  
  The distribution of Trissexodontidae includes the Iberian peninsula, northwest Africa, Azores, Canary Islands, Madeira and Cape Verde.
  
  ## Genera
  
  Genera within the family Trissexodontidae include:
  
  * Caracollina Beck, 1837
  * Gasullia Ortiz de Zárate López, 1962
  * Gasulliella Gittenberger, 1980 - with only one species, Gasulliella simplicula (Morelet, 1845)
  * Gittenbergeria Schileyko, 1991
  * Mastigophallus Hesse, 1918 - with only one species, Mastigophallus rangianus (Michaud, 1831)
  * Oestophora Hesse, 1907
  * Oestophorella Pfeffere, 1929
  * Trissexodon Pilsbry, 1895 - type genus of the family Trissexodontidae
  * Spirorbula Lowe, 1852 - probable classification, from Madeira and Porto Sancto
  * Suboestophora Ortiz de Zárate López, 1962
  
  ## Description
  
  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).
  
  