now first of all - help with disease, sorry to say that there is no cure - I have been collecting for years and it just gets worse.
I said to my wife that I am not greedy as I only want ONE of every thing
Anyway back to your little Stevens, what you have is called a visible loader and is named so because when you operate it you can see the round transfer from the tube mag up to the chamber. The round is held in the claws as per my photo. It does not eject as such just uses the next round push the spend case out, hence the last empty stays in place.
They are great little guns but very complicated to work on, you may see reference to them as "Miserable" or "Impossible" loaders as many people have taken them to bits and have never got them going again.
It aquired the bits of two over Christmas and it took me a few days to make one half decent one from the two (I have done lots of work on guns and still struggled)
If you follow this link http://www.rimfirecentral.com/forums...d.php?t=236969
and the link within the thread you can find lots of info on them.
As for the value I would say $350 - $450 out here in NZ but would not know the value in the US.
Looks like you have one in great condition
Hope this helps