Rishi: Not specified in the excerpt; within Vājasaneyin riddle-cycle tradition.
Devata: Enigmatic/cosmic forms (to be identified in the following mantra).
Chandas: Not securely determinable; prose-like riddle cadence.
Samhita Patha (Devanagari)का स्वि॑दासीत्पू॒र्वचि॑त्ति॒: किᳪ स्वि॑दासीद् बृ॒हद्वय॑: । का स्वि॑दासीत्पिलिप्पि॒ला का स्वि॑दासीत्पिशङ्गि॒ला
Transliterationkā́ svíd āsīt pūrvácittiḥ kíṃ svíd āsīd bṛhádvayaḥ | kā́ svíd āsīt pilippilā́ kā́ svíd āsīt piśaṅgilā́
Translationഏതാണ്, നിശ്ചയമായി, ആദ്യചിത്തി (ആദ്യ ബുദ്ധി)? ഏതാണ്, നിശ്ചയമായി, മഹത്തായ പക്ഷി? ഏതാണ്, നിശ്ചയമായി, പിലിപ്പിലാ? ഏതാണ്, നിശ്ചയമായി, പിശങ്ഗിലാ?
Padapatha (Word Analysis)का । स्वित् । आसीत् । पूर्व-चित्तिः । किम् । स्वित् । आसीत् । बृहत्-वयः । का । स्वित् । आसीत् । पिलिप्पिला । का । स्वित् । आसीत् । पिशङ्गिला ।
Word by Wordस्वित्indeed? I wonder; perhaps (interrogative particle) पूर्वचित्तिःthe former thought/intent; prior conception बृहद्वयःgreat vigor/strength (lit. great ‘vayas’) पिलिप्पिलाPilipilā (a named being/creature; proper name) पिशङ्गिलाPiśaṅgilā (the tawny/reddish one; proper name) 
Viniyoga (Ritual Application)