Horseshoe Crabs: Merostomata

Horseshoe crabs are used for food and as bait to catch various ocean-dwelling animals. Their bodies were once ground up and used as fertilizer. Certain scientific studies of their eyes have led to a better understanding of how the human eye works, resulting in improved treatments for human eye disorders. Their blood contains a substance that is used to identify bacterial contamination, or dirtying, of drugs, surgical equipment, and vaccines, or medicines that are used to protect the human body against disease. Other substances in their blood show promise in fighting viruses and cancer. Their exoskeletons are used in the manufacture of skin lotion, contact lenses, and surgical sutures, or stitches. Chitin (KYE-tehn), an important chemical component of the horseshoe crab's exoskeleton, is used to remove harmful substances from water. It also is taken as a dietary supplement.