tasya-of Lord Vamanadeva; upaniyamanasya-at the time of His being offered the sacred thread ceremony; savitrim-the Gayatri mantra; savita-the sun-god; abravit-chanted; brhaspatih-Brhaspati, the guru of the demigods; brahma-sutram-the sacred thread; mekhalam-the belt of straw; kasyapah-Kasyapa Muni; adadat-offered.