tat putra-pautra-naptrnam
tat-there; putra-of the sons; pautra-of the grandsons; naptrnam-and of the descendants; gotrani-the family dynasties; ca-also; na-not; srnmahe-we do hear of; kalah-time; abhiyatah-have passed; tri-three; nava-nine; catur-yuga-four yugas (Satya, Treta, Dvapara and Kali); vikalpitah-thus measured.