Murasaki 312 Taureans
When we were kids, we all rushed home to see Star Trek or Batman or any of the Irwin Allen Sci-Fi shows on TV. We were a household of Trekkies, but I suppose I was predisposed to be the Trekker (uber-geek.) When we saw them in the 70's when in syndication, it was a contest among us to see who could recognize the episode first. If we couldn't get it before the opening credits, we knew we were in for a rare one. Unfortunately, this episode is not a rarity for I figured it out within the first few seconds.
The Galileo Seven is a cool one where the eponomous shuttlecraft is stranded on a planet beset by large Neanderthals, sort of a Land of the Giants/ Robinson Crusoe blend. Murasaki is the quasar that they investigate and the Taureans are the 12-foot humanoids they encounter. In what may or may not be coincidence, they seem to have a purple tinge to their clothing and skin (though we never do get a close look at them.) I like to think it's intentional for murasaki ムラサキ is the Japanese word for purple.
As an interesting (to me anyway) aside, Lt. Boma was portrayed by Don Marshall who 2 years later starred on The Land of the Giants.