Śāṅkhāyana (Kauṣītaki) Āraṇyaka 2.2

2.2

ŚĀ 2,2
athetāni śīrṣṇyāni śaṃsati | tāni vai trīṇi tṛcāni bhavanti | trīṇi vā asya śīrṣṇaḥ kapālāni bhavanti | tānyevaitaiḥ saṃdadhāti | tāni trīṇi punarevaikaṃ tredhā tredhā tā nava ṛco bhavanti | nava vai śirasi prāṇāḥ | tānyarkavanti bhavanti | tad etasyāhno rūpam ||

ŚĀ 2.2
Then he recites these head verses. They are three triplets. Three indeed are the skull-bones of this head. He unites them with these [verses]. Those three again [become] three times three individually; they are nine verses. Nine indeed are the breaths in the head. They contain the word arka. That is the form of this day.