せたしじみでわありませんでした
瀬田蜆ではありませんでした
setashijimidewārimasendeshita

Noun
Desu Copula

The polite, past negative form of せたしじみ

1. Was not Seta clam.; Was not a Seta clam.

Past/Perfective
Negative
Polite
Formal Register
Usually Written in Kana