Original TOS episode count: 79

Star Trek

Season 1:
  03 Where No Man Has Gone Before
  04 The Naked Time
  10 The Corbomite Maneuver
  12 The Menagerie, Part 1
  13 The Menagerie, Part 2
  14 Balance of Terror
  ..
  22 Space Seed
  23 A Taste of Armageddon
  ..
  25 The Devil in the Dark
  26 Errand of Mercy
  28 The City on the Edge of Forever
  ..

Season 2:
  01 Amok Time
  04 Mirror, Mirror
  06 The Doomsday Machine
  ..
  10 Journey To Babel
  15 The Trouble with Tribbles
  ..
  ..

Season 3:
  ..
  09 The Tholian Web
  15 Let That Be Your Last Battlefield
  ..

Season 1:
  03 Where No Man Has Gone Before
  04 The Naked Time
  10 The Corbomite Maneuver
  12 The Menagerie, Part 1
  13 The Menagerie, Part 2
  14 Balance of Terror
  18 Arena
  22 Space Seed
  23 A Taste of Armageddon
  24 This Side of Paradise
  25 The Devil in the Dark
  26 Errand of Mercy
  28 The City on the Edge of Forever
  30: Operation: Annihilate!

Season 2:
  01 Amok Time
  04 Mirror, Mirror
  06 The Doomsday Machine
  09 Metamorphosis
  10 Journey To Babel
  15 The Trouble with Tribbles
  17 A Piece of the Action
  26: Assignment: Earth

Season 3:
  02 The Enterprise Incident
  09 The Tholian Web
  15 Let That Be Your Last Battlefield
  24 All Our Yesterdays