Multiplexer Logic Diagram - What Is This Component?

[Mitale]

So I have a multiplexer, and the datasheet for it. Now to assist users in use the datasheet contains a logic diagram, which would be much more useful if I knew what this was...

That's my rendition of it. Note that it has 4 ins/outs, one from each side's center. Any ideas?

Also, HEF4053BP is the full part number if you want the rest of the diagram.

 

[Mitale]

I looked at some datasheets for the same chip by other manufacturers and found that it was an analogue switch.