Bad Boy Bonzo

This cute postcard dates from 1931 and was sent to my Dad by one of his sisters. I managed to scan it and it looks quite good. It is Bonzo, an extremely cute and vivacious dog who - apparently - was always involved in some sort of misadventure.

I wonder what kind of dog he is: a mutt, a shar-pei or a bull terrier? Whatever he is, it's way to cute, no?