The Efrosians were a sentient, humanoid species, whose homeworld was a member of the United Federation of Planets by the late 23rd century. Efrosians served in Starfleet by 2286, and an Efrosian served as the Federation President as of 2293. Efrosian males had cranial ridges and were generally seen wearing long, white hair and flowing mustaches. (Star Trek IV: The Voyage Home, Star Trek VI: The Undiscovered Country)