海羊歯

From 海(うみ) (umi, “sea”) + 羊歯(しだ) (shida, “fern”)

海(うみ)羊歯(しだ) or 海羊歯(ウミシダ) • (umishida) 

1. feather star (an echinoderm of the order Comatulida)

As with many terms that name organisms, this term is often spelled in katakana, especially in biological contexts (where katakana is customary).