Add links to files

pages/Coal.html

pages/corals.html

pages/cowry_shell.html

pages/crab.html

pages/deer_mandible.html

pages/foam.html

pages/hourglass.html

pages/kiwi.html

pages/loofah.html

pages/marine_gastropods.html

pages/mussel.html

pages/oak_branch.html

pages/okinawa_forams.html

pages/physalis.html

pages/raspberry.html

pages/rope.html

pages/sea_urchin.html

pages/snail.html

pages/sponge.html