The Dremans were a humanoid species native to the planet Drema IV in the Selcundi Drema system. They had dark orange skin, enlarged foreheads, and fingers which became progressively longer from the index finger to the little (pinky) finger. The Dremans fell under the protection of the Prime Directive, as they were a pre-warp civilization.
In 2365, the Dremans were threatened with extinction when their geologically unstable planet was about to be destroyed. Data violated the Prime Directive when he responded to a radio call from a Dreman named Sarjenka. This, in turn, involved the USS Enterprise-D, and her scientists decided to save the species by shattering the planet's dilithium lattices. (TNG: "Pen Pals")
Background information Edit
According to an internal reference document, listing all the aliens seen in Star Trek: The Next Generation, which was circulated around the time of the production of TNG Season 5, the Dremans were given the description of "Basically humanoid in appearance except for a more prominent cranium, receded hairline and a hand with gradual elongation of the fingers."