भृगुवंश-प्रसववर्णनम्
Genealogical Emanations in the Bhṛgu Line
आयतिर्नियतिश्चैव तयोः पुत्रौ दृढव्रतौ / प्राणश्चैव मृकण्डश्च ब्रह्मकोशौ सनातनौ
āyatirniyatiścaiva tayoḥ putrau dṛḍhavratau / prāṇaścaiva mṛkaṇḍaśca brahmakośau sanātanau
Āyati and Niyati had two sons steadfast in their vows—Prāṇa and Mṛkaṇḍa—known as the eternal Brahmakośas.