Marsupial was the term for a group of animal species, linked together in systematic biology. Kangaroos were an example of marsupials.
The planet Archer IV had several nocturnal marsupials living on it in 2151. (ENT: "Strange New World")
A type of marsupials, living on an unnamed planet in 2153, produced saliva which served as a natural anticoagulant. (ENT: "Bounty")