horseshoe crabs ashore on beige silica sand beach

and animals arthropod arthropods ashore atlantic autumn beach beaches beige brown carapace carapaces cephalothorax coastal crab crabs crawl crawling creatures creepy dead deposition eggs entrance exoskeleton fall falmouth fine grained grass grasses grossed halloween horseshoe invertebrates lay legs limulidae litter marathon marine massachusetts mate mates mating monsters nature nest ocean october out remains sand sea sediments shell silica swim telson weekend wind windblown windy xiphosura xiphosurida yields