noun
swimming crab (Ovalipes punctatus); sand crab
A species of crab found in sandy coastal areas. The name ヒラツメガニ is the standard Japanese common name.
砂浜でヒラツメガニを見つけた。
I found a sand crab on the sandy beach.
The name ヒラツメガニ literally means 'flat-claw crab', from 平 (flat) + 爪 (claw) + 蟹 (crab). The exact derivation is uncertain, but it likely refers to the shape of the claws.