Faunistische aantekeningen, 3. Hoe moet onze grote Arion heten?

Specimens of Arion s. str. from a great number of localities in the Netherlands were dissected in order to know whether they belonged to Arion ater (L.) or Arion rufus (L.) As far as they were mature and well enough preserved for us to be sure of the identification they appeared to belong without exception to Arion rufus (L.). This is, therefore, probably the only species of Arion s. str. occurring in the Netherlands.