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. New Zealand Geological Survey Paleontological Bulletin, 54 1987: 1-140. 37 [Zoological Record Volume 134]