Hardened and thickened epidermis or cuticle, as that of which nails, claws, and hoofs consist, differing from hair or other cuticular structures chiefly in density and massiveness, Specifically? A feeler; a tentacle; an antenna; an ovipositor; also, the tuft of feathers upon the head of sundry birds, resembling a horn; a plumicorn, as that of various owls, A hard protuberance, such as an antler or projection on the head of a giraffe or rhinoceros, that is similar to or suggestive of a horn