>There are two types of Bursa granularis with each having a different
>operculum growth pattern.
Operculum I find unreliable.
Volutomitra banksi may have a minute operculum or, more often, none at all.
Sassia kampyla operculum is variable and may have terminal or central
nucleus. No way are these cryptic spp.
--
Andrew Grebneff
165 Evans St, Dunedin 9001, New Zealand
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