20.When a compound, ending with any of the foregoing irregular words, is made plural, it follows the fashion of the word with which it ends: as, Gentleman, gentlemen; bondwoman, bondwomen; foster-child, foster-children; solan-goose, solan-geese; eyetooth, eyeteeth; woodlouse, woodlice; dormouse, dormice; half-penny, halfpence, half-pennies.