[fusionist]

I believe people call that the cup. It's on very early models, possibly because they were afraid water or debris would get in the snorkle. The design was changed very early on.

Sorry I don't have any more info on removal. What is it bonded to? You remove the snorkle by moving the end closest to you all the way to the right and left and it pops out. Perhaps once it pops the cup will be loose.