This drawing, made by an anonymous artist in the Netherlands, is in the Rijksmuseum Amsterdam. It is entitled ‘Blad met verscheidene monsters, een dwerg, slak en pad’ [Sheet with several monsters, a dwarf, a snail, and a toad]; it is dated 1390-1410. 
In the left-hand middle it shows the larger part of a slug (to the experienced viewer it may look like a semi-slug), covered with a flattish shell-like form. The head of the slug shows two raised, large tentacles and – hardly visible, as the slug is turned away from the viewer, two small tentacles. The neck shows faintly grooves.
This picture might be one of the earliest representations of a slug drawn in the Netherlands. Here only ‘true’ slugs live, viz. with their shell internal and covered by a piece of skin. So the ‘shell’ showing on the figure probably is not an actual shell; only the contours of the shell inside have been drawn, but not the pulmonary pore. Cf. the figure below . As the tail is not figured it is hard to tell if this slug belongs to the Arionidae or Limacidae, although the habitus suggests the former family.
 RM, RP-T-1955-51(V), drawing in black pencil. http://hdl.handle.net/10934/RM0001.collect.28833
 Gittenberger, E., Backhuys, W. & Ripken, Th.E.J. (1984). De landslakken van Nederland: 1–184. KNNV, Hoogwoud (fig. 58).