The Melnorme (prounounced /'mɛlnɔːmeɪ/), as far as we know, are a race of traveling traders in information and technology. They appear as several yellow globs piled on top of each other, with a large smile and a single eye.
The Melnorme's basic culture revolves around exchanges of items, information, and commodities. They believe that giving without receiving is barbaric. The Melnorme lustly search for new information about biological creatures and the ominous Precursor Rainbow Worlds, but to what end is unknown, although, it is probably safe to assume that they sell the information to someone else.
Melnorme are highly sensitive to color. Their bridge has a colorful background that changes to fit their mood or activities. Red is for travel, purple is generally assumed to be for trade (if one manages to find enough credits the Melnorme might even sell the information about turning purple) and when you meet a Melnorme with a blue bridge, know that he is locking his weapons systems on your ship.
It is suspected that the Melnorme are the Mael-Num, or at least their descendants or an offshot species, but the Melnorme say nothing about it. The evidence does point that way, both because of their similar names and because the Kohr-Ah have referred to the Mael-Num as "one-eyed creatures". The fact that the Melnorme keep the locations of their homeworlds secret adds weight to the claim.
The Melnorme are never found in Hyperspace (unless they come looking for you) and are generally encountered only around supergiant star systems. It is suspected, though unsubstantiated, that they use some property of these stars to power some other form of propulsion for even faster interstellar travel; or perhaps not "travel" per se, but some sort of multi-presence, as Trademaster Greenish seems to always be located at every supergiant star in the quadrant.
The Melnorme's Trader ship, while not designed as a warship, is still capable of defending itself. Its charging Powerblaster Fearton Torpedos are known as the one thing that can actually absorb an Ur-Quan Fusion Blast and the Confusion Ray is capable of half crippling a ship's navigation and special systems.