Matsya Purana — Śrāddha Procedure: Types
उपस्पृष्टोदकान्विप्रान् उपवेश्यानुमन्त्रयेत् द्वौ दैवे पितृकृत्ये त्रीन् एकैकमुभयत्र च //
upaspṛṣṭodakānviprān upaveśyānumantrayet dvau daive pitṛkṛtye trīn ekaikamubhayatra ca //
After having the brāhmaṇas touch consecrated water for purification, he should seat them and then recite the appropriate invitatory formulas. For the rite meant for the Devas he should employ two brāhmaṇas, for the ancestral rite (pitṛkṛtya/śrāddha) three, and in a combined rite one for each side.
This verse does not address pralaya; it focuses on dharma in ritual practice—specifically the correct arrangement of priests for offerings to Devas and Pitṛs during śrāddha-related rites.
It prescribes a householder’s (and by extension a king’s) duty to perform rites with proper purity and procedure: purify invited brāhmaṇas with water, seat them respectfully, recite the correct mantras, and appoint the appropriate number of priests for deva- and pitṛ-offerings.
The significance is ritual, not architectural: it standardizes śrāddha protocol—purification by water-touch (upaspṛṣṭodaka), formal seating, and the prescribed number of brāhmaṇas (two for deva-kārya, three for pitṛkārya, or one each when both are performed together).