Old Marlin ID needed.

I picked up an interesting old Marlin this weekend at a gunshow. I was hoping somebody might be able to ID it for me, as it isn't in my rimfire and breakdown books.
I'll be ordering the Numrich catalog, too. I'll be needing parts for it, if I can find them.
The rifle is .22LR, semi-auto, tubular receiver, box magazine (same as the earlie .22 bolt-actions), two recoil springs (top and bottom) with the bottom also acting as hammer spring, heavy walnut stock, cylidrical operating handle, buckhorn rear sight, no scope grooves or holes, probably 7 1/2 pounds weight. There is no model number or serial number. I suspect it was made in the forties or fifties. Any ideas?
This rifle has the extractor missing, and the firing pin groove in the bolt looks battered, freezing the firing pin in fully forward position. It definitely is not a shooter in it's current condition, so I'll need a new bolt assembly if I can find it.
I got cheap, and knew it had problems. It'll make a good addition to my old .22 collection, if I can get it working again.