The name horseshoe Crab is a misnomer. They are not actually crabs. (Atlantic Horseshoe Crab - Phylum Arthropoda : Subphylum Chelicerata : Order Xiphosura : Suborder Xiphosurida : Family Limulidae : Limulus polyphemus)
Editing was done with ACDSee Ultimate 2019. I adjusted the lighting, boosted the contrast, adjusted the levels and used the SmartErase tool to get rid of some dust spots.