atmanam bhagavan ajah
sadhyan ganan pitr-ganan
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Recognizing himself to be full of desire and energy, the worshipful Brahma, the creator of the living entities, evolved from his own invisible form, from his navel, the hosts of Sadhyas and Pitas.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The Sadhyas and Pitas are invisible forms of departed souls, and they are also created by Brahma.