370. Forms of the Stem

Forms of the Stem. In the weak cases (excepting the loc. sing.) the stem-final is , which in the weakest cases, or before a vowel-ending, is changed regularly to r(129). But as regards the strong cases, the stems of this declension fall into two classes: in one of them — which is very much the larger, containing all the nomina agentis, and also the nouns of relationship náptṛ and svásṛ, and the irregular words stṛ́ and savyaṣṭhṛ — the  is vriddhied, or becomes ār; in the other, containing most of the nouns of relationship, with nṛ́ and usṛ́, the  is gunated, or changed to ar. In both classes, the loc. sing. has ar as stem-final.