After anu , ū is substituted for (the a of) ap when the sense is that of a locality.,
Thus अनूपो देशः, but अन्वीपम् when locality is not meant. The long ऊ is taught for the sake of showing how the word is to be analysed; as अनु ऊपः = अनूपः ॥ The form अनूपः could have been evolved with a short उ also, as अनु + उपः = अनूपः ॥ But this analysis is not intended.,