Śrī brahma-saṁhitā 5.13
bījaṁ saṅkarṣaṇasya ca
haimāny aṇḍāni jātāni
The spiritual seeds of Saṅkarṣaṇa existing in the pores of skin of Mahā-Viṣṇu, are born as so many golden sperms. These sperms are covered with five great elements.
The prime divine avatāra lying in the spiritual Causal Ocean is such a great affair that in the pores of His divine form spring up myriads of seeds of the universes. Those series of universes are the perverted reflections of the infinite transcendental region. As long as they remain embedded in His divine form they embody the principle of spiritual reflection having the form of golden eggs. Nevertheless by the creative desire of Mahā-Viṣṇu the minute particles of the great elements, which are constituents of the mundane efficient and material causal principles, envelop them. When those golden sperms, coming out with the exhalation of Mahā-Viṣṇu, enter into the unlimited accommodating chamber of the limited potency (Māyā) they become enlarged by the nonconglomerate great elements.