After the verb gṝ 'to swallow', when preceded by ava, the ātmanepada is used.,
As अवगिरति (he swallows). The root gri to swallow preceded by the preposition ava is Atmanepadi. The verb gri taken in this sutra means to swallow and belongs to the Tudadi class. It is not the gri 'to make sound' which belongs to the kryadi class, because there is no word formed with the latter verb by affixing the preposition ava to it. By sutra (I. .3. 78) this verb gri 'to swallow' would have been Parasmaipadi; the present sutra debars that.
When it is not preceded by ava, it is Parasmaipadi, as गिरति 'he swallows.',