In the chandas (Vedas), the affix liṭ (Perfect Tense) is optionally replaced by the affix kānac,
As अग्निं चिक्यानः 'he consecrated the fire'; सोमं सुषुवाणः 'he pressed the soma juice'. This being an optional affix, is sometimes not employed; as in the examples in the last aphorism.
Why has the word lit been repeated in this sutra, when its anuvritti could have been drawn from the last sutra ? The substitute कानच् replaces not only the special लिट् of sutra 3.2.105, but the general लिट् which comes after the roots in forming the perfect tense; so that the affix कानच् forms verbal adjectives as well as the perfect tense.
This affix comes after those verbs only which take Atmanepada terminations. See 1.4.100. तूतुजान (Rig. Ved. 1.3.6).,