Een zeldzame kleurafwijking van de Zwartgerande tuinslak, Cepaea nemoralis forma hyalozonata, komt nog steeds voor in West-Terschelling

Cepaea nemoralis forma hyalozonata is still living on the dune bordering the Zwarteweg (formerly Duinweg) in West-Terschelling, a Wadden isle in Friesland, the Netherlands. In the past, single specimens of this rare colour form of the Common garden snail Cepaea nemoralis with a white lip and transparent spiral bands had been found on the dune bordering the Duinweg (now Zwarteweg) in West- Terschelling in 2009, 2010 and 2011. In spite of the fact that I did not especially search for it, in autumn 2017 within 10 minutes I found three living specimens of that variety on a low wall separating the foot of the dune and the Zwarteweg. This rare variety is known as ‘forma hyalozonata’; it is probably caused by a genetic aberration. Interestingly, all six specimens from that locality have a yellow shell with five translucent bands, while the lip of the aperture is white.