The king crab or horseshoe crab, now renamed Xiphosura, although the old name persists. It is more closely related to the arachnids than the crustacea. The compound eyes have been widely used in studies on visual systems, but best known to nonzoologists as the source of the very sensitive limulus-amoebocyte lysate (LAL) test used to detect endotoxin which causes rapid clotting. See factor C.
Subjects: Medicine and Health.