Venom sac
A venom sac was a gland that secreted and stored venom. One species that had a venom sac was bunnicorn.

In 2370, as a side effect of Barclay's Protomorphosis Syndrome, Worf developed a venom sac on his neck. When Doctor Beverly Crusher identified it, he spewed its contents on her. ()

In 2399, Kestra Troi-Riker cut the venom sack out of the meat of a bunnicorn, an animal native to Nepenthe. When her mother, Deanna Troi asked her if she did, she jokingly told her that she left it in so that they could vomit black bile and die. ()

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Glands