Śāṅkhāyana (Kauṣītaki) Āraṇyaka 2.5

2.5

ŚĀ 2,5
athaitaṃ prahastakaṃ śaṃsati | tā vai tisra ṛco bhavanti | trīṇi vā asya pāṇeḥ parvāṇi bhavanti | tānyevaitābhiḥ saṃdadhāti | aticchandāḥ prathamā so 'yam aṅguṣṭhaḥ | tasmād ayam aṅguṣṭhaḥ sarvā aṅgulīḥ pratyeti | dakṣiṇaḥ pakṣo rāthantaraḥ | atha vā uttaraḥ pakṣo bārhataḥ | etenaivokto brāhmaṇaḥ | tau vā etau pakṣau bārhatarāthantarau caturviṃśau | caturviṃśatir vai saṃvatsarasyārdhamāsāḥ saṃvatsarasyāptyai ||

ŚĀ 2.5
Then he recites this hand verse. It consists of three verses. Three indeed are the joints of this hand. He unites them with these [verses]. The first is an Atichandas; that is this thumb. Therefore this thumb goes against all the fingers. The right wing belongs to the Rathantara. Then the left wing belongs to the Bṛhat. By this the Brāhmaṇa is stated. Those two wings, belonging to the Bṛhat and Rathantara, consist of twenty-four [verses]. Twenty-four indeed are the half-months of the year, for the attainment of the year.