150
Śrīmad-Bhāgavatam
[Canto 1, Ch. 3]
tataḥ —after that;  saptame —the seventh in the line;  ākūtyām —in the womb of Ākūti;  ruceḥ —by Prajāpati Ruci;  yajñaḥ —the Lord's incarnation as Yajña;  abhyajāyata —advented;  saḥ —He;  yāmā-ādyaiḥ —with Yāma, etc.;  sura-gaṇaiḥ —with demigods;  apāt —ruled;  svāyambhuva-antaram —the change of the period of Svāyambhuva Manu.
TRANSLATION
The seventh incarnation was Yajña, the son of Prajāpati Ruci and his wife Ākūti. He controlled the period during the change of the Svāyambhuva Manu and was assisted by demigods such as His son Yama and others.
PURPORT
The administrative posts occupied by the demigods for maintaining the regulations of the material world are offered to the highly elevated pious living beings. When there is a scarcity of such pious living beings, the Lord incarnates Himself as Brahmā, Prajāpati, Indra, etc., and takes up the charge. During the period of Svāyambhuva Manu (the present period is of Vaivasvata Manu) there was no suitable living being who could occupy the post of Indra, the King of the Indraloka (heaven) planet. The Lord Himself at that time became Indra. Assisted by His own sons like Yama and other demigods, Lord Yajña ruled the administration of the universal affairs.
TEXT 13
अष्टमे मेरुदेव्यां तु नाभेर्जात उरुक्रमः। दर्शयन् वत्मं धीराणां सर्वाश्रमनमस्कृतम् ॥१३॥
aṣṭame merudevyām tu nābher jāta urukramaḥ darśayan vartma dhīrāṇām sarvāśrama-namaskṛtam
aṣṭame —the eighth of the incarnations;  merudevyām tu —in the womb of Merudevī, the wife of;  nābheḥ —King Nābhi;  jātaḥ —took birth;  urukramaḥ —the all-powerful Lord;  darśayan —by showing;  vartma —the way;  dhīrāṇām —of the perfect beings;  sarva —all;  āśrama —orders of life;  namaskṛtam —honored by.