The job of the pivot table is to summarize your source data table based on the criteria you specify in the filter fields (Report Filter, Column Labels, and Row Labels). You can think of it as a very advanced way to arrange and filter your data.
The Limulidae are the only recent family of the order Xiphosura, and contain all four living species of horseshoe crabs: 1  Carcinoscorpius rotundicauda, the mangrove horseshoe crab, found in Southeast Asia. 2  Limulus polyphemus, the Atlantic horseshoe crab, found along the American Atlantic coast and in the Gulf of Mexico.
Biology/Life History of the Horseshoe Crab Horseshoe crabs are among the worldâs oldest and most fascinating creatures. The earliest horseshoe crab species had already inhabited Earth at least 200 million years before the dinosaurs arrived or about 400 million years ago.hitin is a substance found in the shells, or exoskeleton, of horseshoe crabs, as well as other arthropods, such as lobsters, crabs, shrimp, spiders, beetles, and mosquitoes. Chitin has received a lot of attention from scientists because it is non-toxic and biodegradable.