663. Claim by later incumbrancer.

663.     Claim by later incumbrancer.

In the case of successive mortgages, a later mortgagee must make all mortgagees subsequent to himself, as well as the mortgagor, parties in proceedings to redeem a prior mortgage1. If he seeks to redeem any other mortgage than the one immediately prior to himself he must make parties all mortgagees between himself and the mortgage he seeks to redeem2, but he need not make a mortgagee prior to that mortgage a party unless the amount due cannot be ascertained in his absence. As between himself and all behind him, a