The syllable anaṅ is the substitute of the final ūdhas in a bahuvrīhi samāsa ,
As कुण्डमिव ऊधोऽस्याः = कुण्डोध्नी, घटोध्नी ॥ The feminine is formed by adding ङीष् 4.1.25; and these words are always used in this form for the feminine only; no substitution takes place in the masculine, as महोधाः पर्जन्यः; घटोधो धैनुकम् ॥ ऊधस + अन् = ऊधन् 6.4.148. ऊधन् + ङीष् = ऊध्न् + ई (अ being elided by 6.4.134 = ऊध्नी ॥,