What are the metal items on top of an older Nikon lens?

Does anybody knows what the two metal items on top of the lens are used for?

Answer

That's the metering fork, that was used to send information about the aperture setting from the lens to the camera on older camera models. The camera would have a pin that fits in the fork, so that turning the aperture ring moves the pin.

You can see some images of that at Useful Info: Nikon Lenses.