After all other bahuvrīhi samāsa not covered by the foregoing rules, may optionally be added the affix kap,
Thus बहुखट्वकः or बहुखट्वाकः or बहुखट्वः, बहुमालकः or बहुमालाकः or बहुमालः, बहुवीणकः or बहुवीणः or बहुवीणाकः &c. The word शेष denotes all those Bahuvrihi about which no special rule has been given above. How do you explain the forms अनृक्कं साम, बह्वृक्कं सूक्तं, in which the affix कप् is added, though these words are governed by the general rule 5.4.74, and ought to have taken the samasanta affix अ? The affix अ is added to ऋक् when the compound has a special meaning such as अनृचः means 'a boy', बह्वृचः 'a charana'.
Why do we say \after the rest\? Observe प्रियपथः, प्रियधुरः ॥,