noun
Merostomata
A taxonomic class of aquatic chelicerate arthropods, including extinct sea scorpions (Eurypterida) and extant horseshoe crabs (Xiphosura). Used in biological and paleontological contexts.
腿口類にはカブトガニやウミサソリが含まれる。
Merostomata includes horseshoe crabs and sea scorpions.
From 腿 (thigh) + 口 (mouth) + 類 (group), likely a calque of the scientific name Merostomata (from Greek mēros 'thigh' + stoma 'mouth'), referring to the leg-like appendages near the mouth.