The Barzans were a humanoid species native to the planet Barzan II. In appearance they had light-copper to tan skin, with some facial ridges and a hairline set far back from the forehead. When leaving their homeworld, they had to wear a breathing device that provided them with the gases found in the toxic atmosphere of Barzan II.
The Barzans were a resource-poor species, dependent on others for generations. They were technologically only moderately advanced, and they did not have manned space travel. When a wormhole was discovered near their planet, the Barzan resorted to an automated space probe.
It was hoped that the Barzan wormhole would open a new era in prosperity. This hope was a major factor in the Barzans' decision to sell rights to the wormhole to the highest bidder. Unfortunately, the wormhole turned out to be the "proverbial lemon". (TNG: "The Price")