The affix yañ is luk elided in the feminine after the word vataṇḍī when meaning a female descendant of aṅgirasa,
Thus from वतण्डः we get वातण्ड्य in the masculine. In the feminine the यञ् is elided by luk, and we have वातण्ड्य + ङीन् 4.1.73 = वतण्डी \a female descendant of Vatanda of the clan Angirasa.\ Why do we say \of Angirasa?\ Observe वातंड्यायनी formed with 'shpha' under lohitadi rule 5.1.18. When वतण्ड takes अण् under Sivadi class, its feminine is वातण्डी ॥ Though the word is formed with अण् yet in the feminine, there is not ष्यङ् substitution 4.1.78, because Vatanda is a Rishi-Name.,