Over Albinisme bij Gastropoden. III

In this third contribution on albinism in Gastropods, the author gives a more detailed example to demonstrate how the varieties are to understand, if we treat the question on a genetic basis. Further attention is called to different varieties which were hitherto not yet known from the Netherlands. In the neighbourhood of Zeist in the province of Utrecht a population of Arianta arbustorum (L.) was found, consisting of typical specimens together with the variety fuscescens and among them also albinotic shells, wich belong to the var. virescens. At the same locality, Cepaea nemoralis (L.) was observed too and found there exclusively in the form, generally known as var. fascialba Picard, in the band formulas 00300 and 00345. Albino shells of these forms were gathered there; they differ from typical var. fascialba not only in the much paler colour but also in the translucent bands without pigmentation.