There are 4 species of horseshoe crab and all get very large. Living in Maryland, we go to the shore for a couple of weeks each year. Once in a while you'll see one crawling around while you're swimming. I've picked them up a couple of times. I just wish 1 time to go to Delaware during spawning season. I'm told they cover the shore line. The pictures are unbelievable but I want to see it in person. One of the most amazing creatures on Earth.
I have a molted shell in my oceanic bar room. Along with a big reef shark mouth, countless cowrie shells, crown-of-thorns star and other cool things. The horseshoe crab molt is my favorite though.