Śatapatha Brāhmaṇa ("of a hundred paths") 7.1.2.13

7.1.2.13

tasya śira evāhavanīyaḥ | atha ya āhavanīye 'gnirya evāyaṃ śīrṣanprāṇaḥ so 'sya sa tadyatsa pakṣapucavānbhavati pakṣapucavānhyayaṃ śīrṣanprāṇaścakṣuḥ śiro dakṣiṇaṃ śrotraṃ dakṣiṇaḥ pakṣa uttaraṃ śrotramuttaraḥ pakṣaḥ prāṇo madhyamātmā vākpucam pratiṣṭhā tadyatprāṇā vācānnaṃ jagdhvā pratitiṣṭhanti tasmādvākpucam pratiṣṭhā

The Âhavanîya truly is his head; and the fire which is on the Âhavanîya is that vital air of his in the head. And as to why it (the Âhavanîya) has wings and tail, it is because that vital air in the head has wings and tail;--the eye is its head, the right ear its right wing, the left ear its left wing, the vital air its central body, and the voice is the tail (and) the foundation (the feet): inasmuch as the vital airs subsist by eating food with speech (voice), the voice is the tail, the foundation.