The family Physidae (Pulmonata: Basommatophora) is a group of freshwater hermaphroditic snails that have a Holarctic distribution with extension into Central and South America. Despite considerable literature justifying various taxonomic schemes and groupings,

Radix labiata is a widely distributed Palaearctic species. This work aims to improve the knowledge of the intraspecific variability in the more important characters used for determination. To find out which of them are really suitable to distinguish this

The phylogenetic relationships of four nominal south-central Canadian freshwater physids (Physa (sensu lato) skinneri Taylor, 1954, Physa integra (Haldeman, 1841), Physa gyrina (Say, 1821), and the endemic Physa winnipegensis Pip, 2004) were studied by