The affix cha comes after a word denoting 'mountain' in the sense of 'this is his mother-land', when it is a person who lives by arms.,
The word आयुधजीवी means a person who earns his livelihood by arms. The phrase सोऽस्याभिजनः is to be read into the sutra. Thus हृदगोलः पर्वतोऽभिजन एषामायुधजीविनां = हृद्गोलीयाः 'the mercenary soldiers whose ancestral abode is the Hridgola mountain'. So also अन्धकवर्त्तीयाः, रोहितगिरीयाः ॥
Why do we say आयुधजीविभ्यः ? Observe आर्क्षोदा ब्राह्मणाः \the Brahmanas whose native place is Rikshoda mountains\. Why do we say 'mountains'? Observe सांकाश्यका आयुधजीविनः ॥,