Śatapatha Brāhmaṇa ("of a hundred paths") 14.2.2.48

14.2.2.48

tadāhuḥ yadapaśirā apravargyo'tha kenāsyāgnihotraṃ śīrṣaṇvadbhavatītyāhavanīyeneti brūyātkathaṃ darśapūrṇamāsāvityājyena ca puroḍāśena ceti brūyātkathaṃ cāturmāsyānīti payasyayeti brūyātkatham paśubandha iti paśunā ca puroḍāśena ceti brūyātkathaṃ saumyo'dhvara iti havirdhāneneti brūyāt

Here now they say, 'Seeing that the Pravargya is headless, whereby, then, does the Agnihotra become possessed of a head for him?' Let him say, 'By the Âhavanîya.'--'How the New and Full-moon sacrifices?' Let him say, 'By the ghee and the cake.'--'How the Seasonal sacrifices?' Let him say, 'By the oblation of clotted curds.'--'How the animal sacrifice?' Let him say, 'By the victim and the cake.'--'How the Soma-sacrifice?' Let him say, 'By the Havirdhâna.'