The pelvic girdle consists of two large bones of irregular shape, called the Innominate bones.
"Physiology and Hygiene for Secondary Schools"
Francis M. Walters, A.M.
Consequently, if a man gives clothes to a fuller to clean or finish, or to a tailor to mend, and the amount of hire is not fixed at the time, but left to subsequent agreement between the parties, a contract of hire cannot properly be said to have been concluded, but an action is given on the circumstances, as amounting to an Innominate contract.
"The Institutes of Justinian"
Caesar Flavius Justinian
Thus, if a man had one ox, and his neighbour another, and they agreed that each should in turn lend the other his ox for ten days to make use of, and then one of the oxen died while working for the man to whom it did not belong, an action cannot be brought on hire, nor on a loan for use, for a loan for use ought to be gratuitous: but an action should be brought as on an Innominate contract.
"The Institutes of Justinian"
Caesar Flavius Justinian