Trion (species)
From Tardis Wiki, the free Doctor Who reference
The Trion are a race of humanoids from Trion. They look identical to humans and can survive in similar conditions.
- Since the nurse at Turlough's school had no problem when examining Turlough, that would imply that Trions have similar, if not identical, internal structure to humans. (DW: Mawdryn Undead)
Following a civil war on Trion, the losing side and their families were sent to various other planets, such as Earth (though this practice was later abandoned).