Śatapatha Brāhmaṇa ("of a hundred paths") 4.4.1.2

4.4.1.2

ṛtavo vai saṃvatsaro yajñaḥ | te 'daḥ prātaḥsavane pratyakṣamavakalpyante yadṛtugrahāngṛhṇātyathaitatparo 'kṣam mādhyandine savane 'vakalpyante yadṛtupātrābhyām marutvatīyāngṛhṇāti na vā atrartubhya iti kaṃ cana grahaṃ gṛhṇanti nartupātrābhyāṃ kaścana graho gṛhyate

And the sacrifice, forsooth, is the seasons, the year. There, at the morning feast, they are overtly attended to, in that he draws the cups for the seasons; and at the midday feast they are covertly attended to, in that he takes the Marutvatîya libations by means of the two Ritu vessels. Now here (at the evening feast) they neither draw any libation expressly for the seasons, nor is any libation taken with the two Ritu vessels.