[2] The two subdivisions of this large clade are quite diverse: The families currently included in Heterobranchia have historically been placed in many different parts of the taxonomic class of gastropods.

[7] The (sometimes recognized) category Heterostropha within the Heterobranchia, which includes such families as Architectonicidae, the sundial or staircase snails, is primarily characterized by a shell which has a heterostrophic protoconch, in other words the apical whorls are coiled in the opposite plane to the adult whorls.

[8] According to the older taxonomy of the Gastropoda (Ponder & Lindberg, 1997) the Heterobranchia were ranked as a superorder.

Jörger et al. (2010)[9] have redefined major groups within the Heterobranchia: they created the new clades Euopisthobranchia and Panpulmonata.

[9] A cladogram showing phylogenic relations of Heterobranchia as proposed by Jörger et al. (2010):[9] Valvatoidea Orbitestelloidea Cimoidea Rissooidea Acteonoidea Pleurobranchomorpha Nudibranchia Umbraculoidea Runcinacea Anaspidea Pteropoda Cephalaspidea s.s. Siphonarioidea Sacoglossa Glacidorboidea Amphiboloidea Pyramidelloidea Hygrophila Acochlidiacea Stylommatophora Systellommatophora Ellobioidea Otinoidea Trimusculoidea