The affix añ (+\/- a) comes in the sense of 'this is its measure' after the words 1. triṃśat and 2. catvāriśat when it is a Name denoting a brāhamaṇa-book.,
The word वर्ग does not govern this sutra. The indicatory ड् causes the elision of the last vowel with the consonant that follows it 6.4.143. The force of the locative case in ब्राह्मणे is that of अभिधेय and not विषय, i. e. when the word means a Brahmana itself. Had the force been that of विषय, it would have meant, 'in the Brahmana literature'. As त्रिंशदध्यायाः परिमाणमेषां ब्राह्मणानां = त्रैंशानि ब्राह्मणानि 'The Brahmana containing thirty Adhyayas'. So चत्वारिंशानि ब्राह्मणानि ॥ These being the names of certain Brahmanas.,