sa mÄm acintayad devaḥ
praÅ›na-pÄra-titÄ«rá¹£ayÄ
tasyÄhaá¹ haá¹sa-rÅ«peṇa
sakÄÅ›am agamaá¹ tadÄ
saḥ - he (Lord BrahmÄ); mÄm - Me; acintayat - remembered; devaḥ - the original demigod; praÅ›na - of the question; pÄra - the end, conclusion (the answer); titÄ«rá¹£ayÄ - with a desire to attain, understand; tasya - unto him; aham - I; haá¹sa-rÅ«peṇa - in My form of Haá¹sa; sakÄÅ›am - visible; agamam - became; tadÄ - at that time.
Haá¹sa means “swan,†and the specific ability of the swan is to separate a mixture of milk and water, extracting the rich, milky portion. Similarly, Lord Kṛṣṇa appeared as Haá¹sa, or the swan, in order to separate the pure consciousness of Lord BrahmÄ from the modes of material nature.