horseshoe crab

abstract america anatomy animal armoured arthropod arthropoda background barrier beach biology book casing cephalothorzx coastal coastline conceptual crab creative crescentic cumberland details domed environment eyes florida fossil frame georgia gills horseshoe invertebrate island large life limulidae limulus marine merostomata national nature nocturnal north ocean outdoors pattern polyphemus resilience sand sea seahore seashore shape shell spikelike tail texture tourism travel tropical unique unusual usa wildlife woodlouse xiphosurida