The average Lurian was approximately the same height as the average Human (perhaps a few centimeters taller), but had a much broader and heavier body. Lurians were grayish- or tan-skinned beings descended from mammals. Their most noteworthy feature was their narrow, elongated heads. They had wide mouths, puggish noses, and small, deep-set eyes.
Morn (pictured) was the only Lurian ever seen on screen, but it was stated that most Lurians actually did have hair; Morn had just gone bald.
It remains unknown whether a large quantity of children is common for Lurians, or if it is just a coincidence that Morn had 17 siblings.
The species name "Lurian" was thought up by Mark Gehred-O'Connell, the writer of "Who Mourns for Morn?", in which the name made its canon debut. Though a freelance writer, he was allowed to not only name the species but also devise the detail about Lurians having two stomachs. Gehred-O'Connell wasn't entirely certain how that concept came about. However, he admitted it made sense for him to conceive of the idea, since he lived in Wisconsin, a state with a large quantity of cows, which likewise have an elaborate digestive system. The exact location of the Lurian's second stomach wasn't decided, though Supervising Sound Editor Mace Matiosian had to consider this part of Lurian anatomy upon creating the sound of a Lurian regurgitating latinum from it. (Star Trek: Deep Space Nine Companion, pp. 524 & 526)
Morn's prosthetic head was sculpted by Vincent Niebla,  who won an Emmy for his work at only twenty-one years of age.  According to Michael Westmore, the mouth part of the Lurian headpiece was designed so as to allow the actor playing him to speak, should the need arise. However, no Lurian ever spoke a single word on Star Trek: Deep Space Nine. (Michael Westmore's Aliens: Season Four, DS9 Season 4 DVD, Special Features)