いそめじゃなかったです
磯蚯蚓じゃなかったです
isomejanakattadesu

Noun
Desu Copula

The polite, past negative form of いそめ

1. Wasn't a sandworm.; Wasn't an isokiryu (a type of sandworm).

Past/Perfective
Negative
Polite
Casual Register
Usually Written in Kana