Śatapatha Brāhmaṇa ("of a hundred paths") 8.4.3.18

8.4.3.18

ekatriṃśatāstuvateti | daśa hastyā aṅgulayo daśa pādyā daśa prāṇā ātmaikatriṃśastenaiva tadastuvata prajā asṛjyanteti prajā atrāsṛjyanta yavāścāyavāścādhipataya āsanniti pūrvapakṣāparapakṣā evātrādhipataya āsan

'With thirty-one they sang praises,'--there are ten fingers, ten toes, ten vital airs, and the trunk is the thirty-first: it is therewith they then sang praises;--'the creatures were created,'--the creatures indeed were now created;--' the Yavas and Ayavas were the lords,'--the bright and dark fortnights indeed were now the lords.