Snail trouble

[skierguy]

About a week ago I noticed that one of my snails kept falling off the back glass. I would roll him over he would be on his way. Last night rolled him over, he slowly made his way to the front glass. He has what looks like a 1/2 cashew for the back half of his body. WHAT COULD THIS BE. It appears to be part of his body. Has anyone ever seen this before?

 

[fender]

I think you are refering to the "trap door" that most snails have to close off predators. I don't know it's techinical name.

 

[skierguy]

I have never heard of this before. Can you explain it a little more? Where can I find more info on this?