When the palate of the gigantic form was separately manifested, Varuṇa, the director of water in the planetary systems, entered therein, and thus the living entity has the facility to taste everything with his tongue.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
निर्भिन्नं तालु वरुणो लोकपालोऽविशद्धरेः । जिह्वयांशेन च रसं ययासौ प्रतिपद्यते
nirbhinnaṃ tālu varuṇo lokapālo'viśaddhareḥ | jihvayāṃśena ca rasaṃ yayāsau pratipadyate
SB 3.6.13