nityaḥ - continuous; naimittikaḥ - occasional; ca - and; eva - indeed; tathā - also; prākṛtikaḥ - natural; layaḥ - annihilation; ātyantikaḥ - final; ca - and; kathitaḥ - are described; kālasya - of time; gatiḥ - the progress; īdṛśī - like this.

In this way the progress of time is described in terms of the four kinds of annihilation — continuous, occasional, elemental and final.