Bhagavatapurana 2.10.27

2.10.27

utsisṛkṣordhātumalaṃ nirabhidyata vai gudam /
tataḥ pāyustato mitra utsarga ubhayāśrayaḥ //

27. When He thought of the means of discharging the impurity of the essential components of the body, the *anus* was

formed with the organ of evacuation in it and the deity Mittra; and on these two depends the function of discharging.