In this chapter, I will consider the distribution of phrases containing numerals. I will argue that the distribution of certain numeral phrases is limited by gaps in morphological paradigms that have resulted from peculiarities of linguistic evolution. Thus, numerals which only have Nominative and Accusative nominal forms may only occur in positions that are marked with Nominative or Accusative case, regardless of the case mechanisms involved. The adjectival form of those numerals is used in case positions where no nominal numeral of the appropriate case is available, and conversely, in case positions for which there is no available adjectival form, only nominal numerals may occur.