Mbh 12.348.6b

Thus praised by Brahma, the illustrious Purusha, with face turned towards every side, then shook off his slumber, resolved to recover the Vedas (from the Daityas that had forcibly snatched them away). Applying his Yoga-puissance, he assumed a second form. His body, equipt with an excellent nose, became as bright as the Moon. He assumed an equine head of great effulgence, which was the abode of the Vedas. The firmament, with all its luminaries and constellations, became the crown of his head. His locks of hair were long and flowing, and had the splendour of the rays of the Sun. The regions above and below became his two ears. The Earth became his forehead. The two rivers Ganga and Saraswati became his two hips. The two oceans became his two eye-brows. The Sun and the Moon became his two eyes. The twilight became his nose. The syllable Om became his memory and intelligence. The lightning became his tongue. The Soma-drinking Pitris became, it is said, his teeth. The two regions of felicity, viz., Goloka and Brahmaloka, became his upper and lower lips. The terrible night that succeeds universal destruction, and that transcends the three attributes, became his neck. Having assumed this form endued with the equine head and having diverse things for its diverse limbs, the Lord of the universe disappeared then and there, and proceeded to the nether regions. Having reached those regions, he set himself to high Yoga. Adopting a voice regulated by the rules of the science called Siksha, he began to utter loudly Vedic Mantras. His pronunciation was distinct and reverberated through the air, and was sweet in every respect. The sound of his voice filled the nether region from end to end. Endued with the properties of all the elements, it was productive of great benefits.