The last vowel, with the consonant that follows it, is dropped in . pathin 2. mathin and 3. ṛbhukṣin before a weak case-ending beginning with a vowel (before which the aṅga (stem) is called bha -- yaci bham [[1.4.18]].,
As पथः, पथा, पथे, मथः, मथा, मथे, ऋभुक्षः, ऋभुक्षा, ऋभुक्षे ॥ The anuvritti of sarvanamasthana, of course, is inappropriate here: though its anuvritti is current as will be seen in the next sutra.,