drawing of the shell of <i><a href="//commons.wikimedia.org/wiki/Anguispira_alternata" title="Anguispira alternata">Anguispira alternata</a></i>
W. H. Dall (1845-1927)
1905
Dall W. H. 1905 <a rel="nofollow" class="external text" href="https://archive.org/details/alaskaexp13harruoft">Alaska, Volume XIII, Land and Fresh Water Mollusks</a>. New York, Daubleday, Page &amp; Complany, pages 1-157, page 49.