Ancient relatives of horseshoe crab (Limulus polyphemus), were present over 500 million years ago. About 200 million years have passed since the Limulus first appeared on earth. It has persisted nearly unchanged to the present day. Not a true crab, this nine-eyed blue blooded creature is related to spiders and ticks. It lives only on the east coast of North America, ranging from the Bay of Fundy to Central America.

Once considered a major predator of shellfish with commercial value, many towns on Cape Cod placed a bounty on this outlaw. Limulus do eat shellfish, although their diet mostly consists of non-commercial species of shellfish and other marine organisms. During late spring and summer, bounty hunters would collect the crabs, kill them, saving their tails, which would be taken to town hall where they would receive several cents per tail. Bounties on Limulus were discontinued in the early 70's. During this same period of time, commercial harvesters collected large numbers of Limulus from the Chesapeake Bay area which were processed into fertilizer and feed for poultry and livestock. This has been discontinued.

Limulus has been a very important biomedical model for research in vision, neurobiology, cell biology, immunology, biochemistry and drug discovery.

In 1885 W. H. Howell first described unusual properties of the Limulus, one of which was that their blood was blue because it contained copper based pigments. Here at MBL, Dr. Frederik Bang discovered that Limulus blood clotted when exposed to bacterial endotoxins. From his basic research a reagent Limulus amebocyte lysate (LAL), was developed that can detect minute amounts of bacterial toxins. The LAL test has resulted in dramatic improvement in the quality of drugs and biological products for intravenous injection, and has replaced the more expensive and less reliable rabbit test.

H. T. Hartline, in 1967 was awarded a Nobel Prize for his research on the mechanics of human vision. Basic research on visual system of Limulus provided data which he later applied to mechanics of human vision. Dr. Robert Barlow, was a student in his lab during this period, and continues to explore the neural, visual and behavioral system of Limulus. Robert Aims, Peter Armstrong, Jack Levin, and Norman Wainwright continue to use Limulus in their research here at MBL.

For nearly 100 years, until 1994, a drawing of the Limulus with the words "The Test of Years" was the trade mark of the Aquatic Resources Division ( formally, Supply Department, Marine Resources Department) at MBL appeared on all stationary, labels and catalogs. Photos of department collection vehicles in the 50's had decals 24" in diameter affixed to the doors.

Read "Eyes Confess the Secrets of the Brain" for more on the contributions of Limulus to vision research.