CMOS transmission gate symbol with X, Y, and (not Y) logic inputs—what does it mean?

Hi,
I recently saw the following symbol described as a tri-state gated buffer or something similar. It had three logic signals attached to it. (not Y) to the bubble on top, X to the middle and Y to the bottom connection. The output went to another regular logic gate. I've seen regular tri-state buffers before and I've found plenty of them from searching online, but nothing like this. I did find a graduate student paper that used a similar symbol for an SR latch in a memory circuit but it didn't describe much about it.

Nevermind, I found it. It's a CMOS transmission gate.

http://www.youspice.com/ys/en/project/cmos-transmission-gate.3sp

Thanks

Yes, I've seen it used to represent the analog switches in CMOS devices such as CD4016, CD4066, etc. for instance.