A revision of the fossil and living gastropods related to Plesiotriton Fischer, 1884 (Family Cancellariidae, Subfamily Plesiotritoninae n. subfam.). With an appendix: Genera of Buccinidae Pisaniinae related to Colubraria Schumacher, 1817 - Beu, A. G.; Maxwell, P. A. (New Zealand Geological Survey Paleontological Bulletin, 1987)