: Unlike most mollusks, Arcidae often contain hemoglobin in their hemocoel, giving them a red-colored body and the name "blood cockles". This adaptation may aid survival in low-oxygen environments like mud.
: A long, straight hinge line with numerous small teeth. arcidae
: Though rare, some species are found at abyssal depths and in polar seas. : Unlike most mollusks, Arcidae often contain hemoglobin