Mercedes 170 H 1936
2014 Louwman Museum - Den Haag (NL)
There were a number of cars that lead to the "Kraft durch Freude" (KdF) auto in 1938 (factory designation VW38), which became the Volkswagen Beetle after the war. Various Germanic manufacturers (for instance also NSU and Zundapp) were experimenting with a rear engined, streamlined, affordable car since the early 1930s. The Volkswagen Beetle became the synthesis of that.
In the case of Mercedes it started with the 130 model in 1934, followed by the 150 in 1935 and this 170 H in 1936. Instead of boxer engines they had traditional, watercooled, 4 cylinder in-line engines in the rear. None of these models were successful however and few are left.