When follows is the augment of a stem ending in vatu,
The word डटि is understood here also. The words ending in वतु are Numerals (1. 1. 23): and they will take डट् by 5.2.48; the present sutra declares the augment. Thus यावतां पूरणो = यावतिथः, तावतिथः, एतावतिथः ॥,