shells of <i>Potamopyrgus antipodarum</i> f. <i>carinata</i> (left) and <i><a href="//commons.wikimedia.org/wiki/Potamopyrgus_antipodarum" title="Potamopyrgus antipodarum">Potamopyrgus antipodarum</a></i> (right). Locality: Baltic Sea (Hanko Penninsula coast, area of Tvarminne Zoological Station, Finland). Scale bar is 0.5 cm.
Mikhail O. Son
CC BY 2.0
<p>Figure 3 from:
</p>
Dmitry P. Filippenko &amp; Mikhail O. Son <i>The New Zealand mud snail Potamopyrgus antipodarum (Gray, 1843) is colonising the artificial lakes of Kaliningrad City, Russia (Baltic Sea Coast)</i>. Aquatic Invasions (2008) Volume 3, Issue 3: 345-347.