ayam-this process of creation and annihilation; tu-but; brahmanah-of Brahma; kalpah-his one day; sa-vikalpah-along with the duration of the universes; udahrtah-exemplified; vidhih-regulative principles; sadharanah-in summary; yatra-wherein; sargah-creation; prakrta-in the matter of material nature; vaikrtah-disbursement.