Lamb, Pg 229
Look more like this group than " Horn Snails" - Cerithidea
Found in the river
Aquatic Snail. Mollusca, Gastropoda
More info http://cretenature.blogspot.co.uk/2014/11/the-waterfall-of-milonas.html
The Neotaenioglossa is an taxonomic name for a large group of mostly sea snails. The name was originally created by Haller in 1882. Ponder and Warén (1988), and Marquet (1997), assigned this name to the superorder Caenogastropoda. ITIS considers the order Neotaenioglossa to be a synonym of Cerithioidea Férussac, 1819 .