A lieutenant from the Enterprise's tactical staff who beamed down to Cestus III with Kirk in 2267 and was killed when the hidden Gorn force opened fire on the landing party.
Lieutenant Lang appears in the episode Arena. He is one of the officers Kirk brings to Cestus III in response to what seems to be Commodore Travers's request for a tactical conference, along with Spock, McCoy, Kelowitz and O'Herlihy.
Once the party realises the outpost has been destroyed, Kirk sends Lang and Kelowitz to scout the flank while Spock's tricorder picks up cold-blooded life forms nearby. The enemy begins bombarding them with disruptor mortars, and O'Herlihy is disintegrated.
Kelowitz makes it back to report that Lang has been killed. Kirk then breaks into the outpost's arsenal and drives the attackers off with a grenade launcher. Lang was played by James Farley.