The Locative -7th case affix is not elided after a stem ending in a consonant or a short a in the name of atax of the Eastern People when the second member begins with a consonant.,
Thus सूपेशाणः, दृषदिमाषकः, हलेद्विपदिका, हलेत्रिपदिका ॥ All these are names of taxes, and would have retained the Locative ending even by the last rule. The present rule makes a niyama or restriction, which is threefold, namely (1) when it is the name of a tax, and no other word, (2) when it belongs to the Eastern people and no other people, (3) and when the second member begins with a consonant.
Why do we say when it is the name of a tax.? Observe अभ्यर्हितेपशुः = अभ्यर्हितपशुः ॥ It is the name of 'a duty or dues', but not of a 'tax'. Why do we say \of the Eastern people\? Observe यूथेपशुः = यूथपशुः ॥ Why do we say 'before a second member beginning with a consonant'? Observe अविकटे उरणः = अविकटोरणः ॥ So also नद्यां दोहनी = नदीदोहनी ॥ For accent of these words see 6.2.65.,