The affix kha (īna) comes optionally in the senses taught in pantho ṇa nityam [[5.1.76]], tamadhīṣṭo bhṛto bhūto bhāvī [[5.1.80]] after the word samā , forming a dvigu samāsa (Numeral Determinative Compound).,
In the alternative ठञ् will also apply. The Vartika taught in 5.1.20 (प्राग्वतेः संख्यापूर्वपदानां तदन्तग्रहणमलुकि) applies here also. Thus द्विमासीनः or द्वैमासिकः, त्रिमासीनः or त्रैमासिकः ॥,