Śatapatha Brāhmaṇa ("of a hundred paths") 11.2.6.4

11.2.6.4

pañca prayājāḥ ima evāsya te śīrṣaṇyāḥ pañca prāṇā mukhamevāsya prathamaḥ prayājo dakṣiṇā nāsikā dvitīyaḥ savyā nāsikā tṛtīyo dakṣiṇaḥ karṇaścaturthaḥ savyaḥ karṇaḥ pañcamo'tha yaccaturthe prayāje samānayati tasmādidaṃ śrotramantarataḥ saṃtṛṇaṃ cakṣuṣī ājyabhāgau sa vidyāccakṣuṣī eva ma etāviti

The five fore-offerings are these its five (outlets of the) vital airs in the head;--the first fore-offering is its mouth, the second the right nostril, the third the left nostril, the fourth the right ear, and the fifth the left ear. And inasmuch as at the fourth fore-offering he pours together (the ghee), therefore this ear is, on the inner side, connected by a channel (with the other). The two butter-portions are the eyes: let him know that these are his own eyes.