The Malcorians were a humanoid species native to the planet Malcor III. They were a people who believed that they were the highest form of life and that their planet was at the center of the universe. Their planet had a unified government led by a chancellor. (TNG: "First Contact")
Malcor III was governed by a planetary government, led by an elected Chancellor. The Chancellor's second in charge was a Vice-Chancellor, who was often assigned tasks the Chancellor was too busy to attend to. The chancellor during the late 2360s was Avel Durken.
Next in line of government was a series of ministers assigned to different divisions of government. A Minister for Security was assigned with all planetary security measures, including those presented by external forces. The Minister of Security during the late 2360s was Minister Krola. The Minister of Science was assigned to all scientific pursuits, which in the 2360s mainly focused on the development of warp travel and new spacecraft and pursuits. The Minister of Science in the 2360s was Mirasta Yale, a scientist who was a leader in the scientific community. All ministers were assigned the task of reporting to the Chancellor every morning on their established fields.
In distant history, before the planet's governments were united, it had nation-states which would sometimes conquer others, often using the greeting "we are your friends".
The mid-24th century marked a period of significant scientific growth for the Malcorians, to the point that it became a political issue. When Durken came to power, he had a lot of support, which he used to enact social reforms and support scientific endeavors at a rapid pace. The Space Bureau had even finished a prototype design for their first warp-capable spacecraft in 2367 and were about to initiate their warp program. However, a significant fraction of the population thought progress was being made too quickly and held on to more traditional ways of life. This eventually turned into conflict, and riots broke out.
Throughout the early 2360s, the United Federation of Planets had undercover cultural observers stationed around Malcor in preparation for possible first contact. The crew of the USS Enterprise-D assisted those efforts and was undergoing the final preparations for first contact when Commander Riker was injured in a riot and captured when the medical staff found he was an alien. Even though Captain Jean-Luc Picard proactively contacted Durken to form a relationship and get Riker back, Durken decided his people were not ready for first contact and postponed the warp program. (TNG: "First Contact")
A form of liquid measurement was the octare.
According to the script "The Malcorians are humanoid with a slight difference in facial features... their hands are shaped like mittens without fingers (and if this is a difficult makeup job, they can all wear gloves.)" The script's pronunciation states their name should be pronounced as "mahl-KOHR-ee-an".
According to Michael Westmore, "Because we were showing a race whose development ran parallel to 20th century Earth, we didn't want the Malcorians to look too alien. I designed a forehead piece to change their faces and a set of hands that weren't quite human-looking, but would perform the same functions. The fingers were webbed together, and had little suckers on the end that could be used to grip objects. There was a little cap that covered the thumb, which also had a sucker on it." (Star Trek: The Next Generation Makeup FX Journal, p. 76, 78)
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 Malcorians were described as "Humanoid, mitten-like hands and feet – suction cups at the palm and 'fingertips'; cranial lobe with upper nostril like nasal openings."
In the novelization of All Good Things, there was a Malcorian female serving aboard the USS Pasteur as a transporter operator in the anti-time future.