Multiple leads on capacitor?

Check out this data sheet of the Vishay capacitors that look alike the one you showed. It seems the extra pins are for mounting, since it's a big capacitor.

This could very well be multiple capacitors in one package, probably with a shared negative (-). The legend states "1 = 220 uF". Are there also markings like "2 = xyz uF", and are the connections by any chance marked -, 1, 2, etc?

For completeness, motor "capacitors" are often more than one actual capacitor bundled into a single package, and thus have more than two leads. A very common example is the start/run capacitor usually found in air-conditioning units.

I don't think your image is one of these though.