Different identifying marks in Harpa species?

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<a href="http://openlibrary.org/works/OL787280W/Conchs_Tibias_and_Harps_--_A_Survey_of_the_Molluscan_Families_Strombidae_and_Harpidae" target="_blank"><!-- m --><a class="postlink" href="http://openlibrary.org/works/OL787280W/Conchs_Tibias_and_Harps_--_A_Survey_of_the_Molluscan_Families_Strombidae_and_Harpidae">http://openlibrary.org/works/OL787280W/ ... d_Harpidae</a><!-- m --></a>

<a href="http://www.amazon.com/gp/product/0876666292?tag=openlibr-20" target="_blank"><!-- m --><a class="postlink" href="http://www.amazon.com/gp/product/0876666292?tag=openlibr-20">http://www.amazon.com/gp/product/087666 ... penlibr-20</a><!-- m --></a>