In the yajurveda , when the gravely accented a of avapathās follows e or o , the vowels retain their original form.,
Thus त्री रुद्रेभ्यो अवपथाः ॥ The word अवपथाः is 2nd person Singular Imperfect of वप् in the Atmanepada. Thus अ + वप् + शप् + थास् ॥ The अ is grave by (VIII. I. 28). When it is not gravely accented, the अ drops. As यद्रुद्रेभ्योऽवपथाः ॥ Here अ is not grave by virtue of (VIII. I. 30).,