ṣ is substituted for the s of saha after pṛtanā and ṛta,
Thus पृतनाषाहम्, ऋताषाहम् ॥ Some divide this sutra into two; as (1) सहेः; (2) पृतनार्त्ताभ्यां च ॥ So that the rule may apply to ऋतीषहः also. The word ऋति is lengthened by 6.3.116, in sanhita : and the ष change takes place in sanhita only. Otherwise the form is ऋतिसहम् ॥ The word च 'and' in the sutra includes words other than those not mentioned in it. The word ऋतीषहं would be valid by this also.,