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.
Horseshoe crabs donât have antennae or jaws and have six pairs of legs. Horseshoe crabs are in a class of their own: Merastomata, which means âmouth surrounded by legs.Horseshoe crab fossils, similar in form to the ones you see in estuaries today, are found in rocks over 450 million years old.ntroduction Atlantic horseshoe crabs are one of the many important organisms living in estuaries along the East and Gulf coasts of the United States. They are abundant from Virginia to New Jersey with the largest population of spawning horseshoe crabs found in the Delaware Bay, site of the Delaware NERR.