The Terrians looked a lot like...

..the Space Jockey from the original Alien movie but in human size proportion.

Very similar right down to the body ribbing and skull and face construction. Still a cool and interesting take on a race...the way they pop out of the ground is incredible - a really neat effect!

And I really like Netflix for posting the older shows like this up for enjoyment...I missed out on this first time around. Only caught a couple of shows mid season then it was gone.