Centauri, the funny-shaped Federation Ambassador to Peladon, is described as an hermaphrodite hexapod. That means he/she/it walks on six legs. But we can clearly SEE six more tentacle-like arms waving gaily out the front.
The rest is simple maths.
Of course in a completely different TV series, Londo Mollari, the funny-shaped Centauri Ambassador to Babylon 5, lets slip that the Centauri there have six prehensile, er, tentacles, sticking out the front too. And along with their four other limbs that must make them very nearly related to Alpha.
Though that probably makes Alpha even RUDER than she/he/it looks!
Actually, the fact that we can’t SEE the six feet on the floor, leads to the assumption that rather than being naked under that fetching yellow shower-curtain, Centauri is ACTUALLY wearing a floor-length dress with a bit of a ruff at ankle height. He/she/it likes a bit of rough, says Daddy. It’s green a tight collar. So it’s like the Centauri equivalent of a flesh-coloured roll-neck pullover. Very Nineteen Seventies!
Why not check out Daddy Alex's preview, and then go and see for yourself!