The affix kap is added to a bahuvrīhi samāsa the last member of which ends in in when a feminine word is denoted,
Thus बहवो दण्डिनोऽस्यां शालायां = बहुदण्डिका शाला ॥ So also बहुछत्रिका; बहुस्वामिका नगरी, बहुवाग्मिका सभा ॥ Why do we say when denoting a feminine? Observe बहुदण्डी राजा or बहुदण्डिकः ॥ The latter form is derived by adding कप् optionally under 5.4.154.,