The Cygnians are a species native to the Alpha or Beta Quadrant.
A medical paper published by the 23rd century explored the diseases that have been known to affect the respiratory system of Cygnians. (TOS: "Obsession") Information on this topic would remain a valid medical source well into the 24th century. (DS9: "Explorers")
- According to the Alan Dean Foster novelization Star Trek Log 4 and Star Trek: SCE, Magen from TAS: "The Time Trap" was a Cygnian from Omega Cygni. It is not clear, if Omega Cygni and Cygnet XIV is related, but the novels The Romulan War - Beneath the Raptor's Wing and Synthesis suggest, they are.
- The female doctor from the USS Kelvin could be a cygnian too.