In Discworld there are 8 Virtues: Patience, Chastity, Silence, Charity, Hope, Tubso, Bissonomy and Fortitude." and are displayed in the library of Unseen University in Ankh-Morpork. The seven Virtues in Roundworld are Hope, Charity, Faith, Justice, Temperance, Fortitude, and Prudence and are often displayed in niches in churches throughout Europe.
The Discworld Virtues of Bissonomy and Tubso are so little remembered that no one knows what they represent. According to Chaffinch's Ancient and Classical Mythology of Discworld, there was a Goddess Bissonomy who had two children by the great god Blind Io, and who was later punished for the sin of throwing a mole at the shadow of the Goddess Resonata. The god Epidity took it on himself to administer this punishment, which turned Bissonomy into a shower of oysters. So we can gather that if the oysters fell into a congenial quiet tidal estuary, Bissonomy may live on in mollusc form, living the simple bivalvian lifestyle. In Going Postal, Moist von Lipwig looked at the statue in the Library and from certain evidential detail, surmised it had to do with kettles and a bunch of root vegetables which looked like parsnips.
In The Compleat Ankh-Morpork, there is an advertisement for the unique business of the haruspex Jeremy Extispicy, Clairvoyant And Sausage Maker, who claims to be able to predict the future from pig entrails. One mystical cut of the pig is called The Rings of Bissonomy. This adds a Bissonomy association to either rings or pigs or possibly both. The Rings of Bissonomy run roughly along the line of the pig's backbone to just before the tail, where they meet the dispiriting Mount Of Unfathomable Harmonies. This may well be related to the quaint rural custom of hog-ringing, referred to in The Celebrated Discworld Almanak. Nothing further is mentioned of Bissonomy's children.
Significantly, Prudence, Justice, Temperance and Faith are not virtues in Discworld while Patience, Chastity and Silence are. Common to both are Hope, Charity and Fortitude.