Amniotes amniotes hard-shelled eggs Eggs Amniote Amniotes hard-shelled eggs AMNIOTE eggs amniotes ucmp.berkeley.edu Amniotes amniotes amniote vertebrates AMNIOTE amniote vertebrates AMNIOTE hard-shelled eggs Introduction to the Amniota Introduction to the Amniota Amniote hard-shelled eggs UCMP Amniota