Bhagavatapurana 3.6.14

3.6.14

nirbhinne aśvinau nāse viṣṇor āviśatāṃ padam /
ghrāṇenāṃśena gandhasya pratipattir yato bhavet //

14. Then the nostrils of Vishnu were evolved, which being their own place the twin gods Aswins entered along with the sense of smell, their power, by which the world attains the sense of smell (perceives smell).