drawing of the shell of <i><a href="//commons.wikimedia.org/wiki/Bithynia_tentaculata" title="Bithynia tentaculata">Bithynia tentaculata</a></i>
Ehrmann, Hermann Felix Paul (* 21st December 1868 – † 6th October 1937; Germany)
1933
scanned (and retouched) by <a href="//commons.wikimedia.org/wiki/User:Snek01" title="User:Snek01">User:snek01</a> from V. I. Zhadin: Molljuski presnych i solonovatych vod SSSR. - Moscow, 1952,  62. - Image number 184.