The Ovions were a hexapodic (six-limbed) species native to the Ovion system in the Delta Quadrant.
In 2377, the Ovions held a symposium about spaceborne pathogens, and requested that The Doctor from the USS Voyager speak. However, Commander Chakotay refused The Doctor's request to attend, since the Ovion system was two weeks behind them. (VOY: "Flesh and Blood")
This species was only mentioned in dialogue.
The Ovions were also a hexapodic species in Battlestar Galactica. (Star Trek Encyclopedia, 4th ed., vol. 2, p. 117