Srimad Bhagavatam Canto 02, Chapter 05, Text 35

SB 2.5.35

sa eva purusas tasmad
andam nirbhidya nirgatah
sahasrorv-anghri-bahv-aksah
sahasranana-sirsavan
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
The Lord [Maha-Visnu], although lying in the Causal Ocean, came out of it, and dividing Himself as Hiranyagarbha, He entered into each universe and assumed the virat-rupa, with thousands of legs, arms, mouths, heads, etc.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
The expansions of the planetary systems within each and every universe are situated in the different parts of the virat-rupa (universal form) of the Lord, and they are described as follows.
Srimad Bhagavatam Canto 02, Chapter 05, Text 34
Srimad Bhagavatam Canto 02, Chapter 05, Text 36