De Jur was an American company which imported amateur movie equipment under its own name (a common practice). In the early 50s they dipped a toe into the still camera market by importing German Neidig cameras, which were made in Plankstadt, West Germany. There they were known as the Perlux line, and this is a Perlux IIa. But Neidigs were also rebadged and sold under the Adox, Amsco, and Bauer brands.
Cute camera. Very squat and heavy for its size. It has that funky double-action winder on the top (takes two full strokes to advance and cock the shutter) and the raft of little idiosyncracies common to German cameras.
Supposedly this is an interchangable mount, though I've never tried removing the lens. Retography said it's a 39mm that's compatible with my Braun Super Paxette, but (of course and unfortunately) not with Leica.