Śatapatha Brāhmaṇa ("of a hundred paths") 3.8.3.34

3.8.3.34

atha yānyupabhṛtyavadānāni bhavanti | tāni samānayamāna āhāgnaye sviṣṭakṛte 'nubrūhītyāśrāvyāhāgnaye sviṣṭakṛte preṣyeti vaṣaṭkṛte juhoti

Thereupon, while pouring together the meat portions that are for the upabhrit, he says (to the Hotri), 'Recite (the invitatory prayer) to Agni Svishtakrit (the maker of good offering)!' Having called for the Sraushat, he says (to the Maitrâvaruna), 'Prompt for Agni Svishtakrit!' and offers as the Vashat is pronounced.