This is what the insides of an Epson C80 cartridge look like. It is a new design for Epson. They will be using this on the new 950 and 2200 printers as well. The unique part of this cartridge is that there are no sponges, nor are there any collapsing bags. It is done by a series of chambers feeding each other.

On the left you can see the air filter. On the right see the small ink filter. Notice the "Tang" on the left. When you insert the cartridge into the printer for the first time, this "Tang", punctures a membrane that lets air into the cartridge

This is the Epson T048 cartridge