Tandonia reuleauxi (Clessin, 1887)
External: Black to brown-black body, with lighter sides; weak grooves in skin; genital opening far towards anterior of mantle; keel along along entire dorsum; gray-white sole; mucous clear, and opaque white to slightly blue-green when perturbed (Wiktor 1996).
Internal: Cylindrical epiphallus with longitudinal folds inside, a bit wider at apex; penis and epiphallus undifferentiated; penis wide at its base and with papilla inside; spermatheca ovate, with thick-walled duct shorter than spermatheca itself, and longitudinal folds inside spermatheca; cylindrical oviduct; short vagina and atrium; accessory glands form "small rolls," around intersection of spermatheca duct, atrium, and vagina; spermatophore with bifurcated spines covering flagellum part, nothing on its mid-section, and rows of multi-branched spines on its posterior (Wiktor 1996).
Juveniles: may be beige in color (Wiktor 1996).
To 100 mm long extended; preserved: to 55 mm long, 13 mm wide, mantle 20 mm long (Wiktor 1996).
Dalmatia, Bosnia and Herzegovina, and Montenegro (Wiktor 1996).
Shady, moist valleys and thickets; shelters under rocks (Wiktor 1996).