एङि पररूपम्

The words आत्, उपसर्गाद्धातौ are understood here. In an upasarga ending in अ or आ followed by a root beginning with ए or ओ, the vowels coalesce and the single-substitute is the form of the second vowel (पररूप) ॥ This debars Vriddhi taught in (VI. I. 88). Thus उपेलयति, प्रेलयति, उपोषति, प्रोषति ॥ Some read into this sutra the option allowed by (VI. I. 92), according to them the para-rupa substitution is optional in the case of Denominative roots. Thus उपेडकीयति or उपैडकीयति, उपोदनीयति or उपौदनीयति ॥

Vart:- The Para-rupa substitution takes place in the case of शकन्धुः &c. As शक + अन्धुः = शकन्धुः, कुल + अटा = कुलटा, सीम + अन्तः = सीमन्तः 'hair'; when not referring to 'hair', the form is सीमान्तः ॥

Vart:- The Para-rupa substitution takes place when एव follows a word, and the sense is not that of 'appointment'. Thus ह + एव = इहेव; अद्य + एव = अद्येव ॥ When the sense is that of नियोग, the Vriddhi takes place: as इहैव भव, माऽन्यत्र गाः ॥

Vart:- The Para-rupa substitution takes place optionally when ओतु and ओष्ठ are compounded with another word: as स्थूल ओतुः = स्थूलौतुः or स्थूलोतुः, so also बिम्बौष्ठी or बिम्बोष्ठी ॥ When not a compound, the Vriddhi is compulsory: as तिष्ठ देवदत्तौष्ठं पश्य 'Stay Devadatta, see the lip'.

Vart:- In the Vedas, the para-rupa substitution takes place when एमन् &c. follow. Thus अपां त्वा एमन् = अपां त्वेमन् ॥ So also अपां त्वा ओद्मन् = अपां त्वोद्मन् ॥,