Copyright problem removed 

This article was based on Powell A. W. B., New Zealand Mollusca, William Collins Publishers Ltd, Auckland, New Zealand 1979 ISBN 0-00-216906-1. It has been revised on this date to eliminate a probable copyright violation of that book. Earlier text must not be restored, unless it can be verified to be free of infringement. For legal reasons, we cannot accept copyrighted text or images borrowed from other web sites or printed material; such additions will be deleted. Contributors may use external websites as a source of information, but not as a source of sentences or phrases. Accordingly, the material may be rewritten, but only if it does not infringe on the copyright of the original or plagiarize from that source. Please see our guideline on non-free text for how to properly implement limited quotations of copyrighted text. Wikipedia takes copyright violations very seriously, and persistent violators will be blocked from editing. While we appreciate contributions, we must require all contributors to understand and comply with these policies. (For background on this situation, please see the related administrator's noticeboard discussion.) Thank you.   (talk)