The Haliians are a species from the Federation planet Halii. Externally, they are distinguished by the fact that their foreheads have a slight bulge above each eyebrow. They also have a distinctive crevice between the brows, on the bridge of the nose.
The Haliians are a telepathic species, although they are limited to person to person empathy. A special crystal called a canar, when held by an Haliian, has the potential to greatly increase their telepathic abilities and allow them to "bond" with others and share their thoughts. One of their holidays is the Batarael, at which a traditional song called the Horath is sung. Aquiel Uhnari and her sister Shianna were Haliians. (TNG: "Aquiel")