Matsya Purana — The Attendant Hosts of the Sun and Moon: Monthly Gaṇas
काद्रवेयौ तथा नागौ कम्बलाश्वतरावुभौ गन्धर्वौ धृतराष्ट्रश्च सूर्यवर्चाश्च तावुभौ //
kādraveyau tathā nāgau kambalāśvatarāvubhau gandharvau dhṛtarāṣṭraśca sūryavarcāśca tāvubhau //
Likewise, the two Kādraveya Nāgas—Kambala and Aśvatara—are named; and among the Gandharvas, the two are Dhṛtarāṣṭra and Sūryavarcā.
This verse is not a Pralaya teaching; it functions as a cosmological catalogue, naming specific Nāgas and Gandharvas as part of the ordered population of the universe.
Indirectly, such catalogues support Purāṇic education: a king or householder is encouraged to learn sacred lineages and cosmic orders (itihāsa–purāṇa knowledge) as part of dharma and cultural memory.
No Vāstu or ritual procedure is specified here; the verse is primarily nominative, preserving traditional names within Purāṇic cosmology rather than giving temple-building or rite instructions.