The syntypes of Carychium reticulatum Hauffen, 1856 and Carychium bidentatum Hauffen, 1856, thought to be lost to science, have been rediscovered in a recent inventory of the shell collection of Domink Bilimek (1813–1884) at the University of Natural Resources and Life Sciences in Vienna, Austria (BOKU). In this work, we present (1) the historical context of the Dominik Bilimek and Heinrich (also: Henrik) Hauffen collections and (2) provide a contemporary image dataset of Hauffen’s original material while considering today’s taxonomic understanding of the genus Zospeum. We clarify the taxonomic status of the syntypes by using light microscopy, Scanning Electron Microcopy (SEM) and 3D X-ray Micro-CT data in conjunction with Hauffen’s original illustrations and compare them to contemporary investigations of their closest congeners. Analysis of Zospeum reticulatum (Hauffen, 1856) is supported by historical documentation from Heinrich Hauffen’s original annotations and Bilimek’s diary entries, as well as from individual collection labels in Hauffen’s own script (verified by archive material from the Archive of the National Museum of Slovenia, NMS). Hauffen’s descriptions are based on apertural morphology and shell microstructure. Our re-investigation of Zospeum reticulatum provides corroborating evidence supporting its assignment to Zospeum spelaeum (Rossmaessler, 1839) while that of Carychium bidentatum corroborates its status as junior synonym of Zospeum costatum (Freyer, 1855).