"Arcubus" Quotes from Famous Books
 ... -ubus, instead of -ibus, occurs in the Dative and Ablative Plural of artus (Plural), limbs; tribus, tribe; and in dis-syllables in -cus; as, artubus, tribubus, arcubus, lacubus. But with the exception of tribus, all these words admit the forms in -ibus as well as those ...
— New Latin Grammar • Charles E. Bennett |
