In a aṅga (stem) in an with a preceding m with the exception of varman , the ending an does not remain unchanged before the Patronymic affix aṇ ,
Thus सुषाम्णोऽपत्यं = सौषामः, चान्द्रसामः from चन्द्रसामन् ॥ Why do we say 'preceded by म्'? Observe सोत्वनः, preceded by व ॥ Why do we use 'Patronymic'? Observe चर्मणा परिवृतो रथः = चामर्णः, the अन् not being changed by 6.4.167. Why do we say 'with the exception of वर्मन'? Observe चक्रवर्मणोऽपत्यं = चाकवर्मणः ॥
Vart:- Optionally so in हितनामन्, as हितनाम्नोऽपत्यं = हैतनामः or हैतनामनः ॥,