Try these links for more information on devonian armoured fish:   http://encarta.msn.com  (search for placoderms) http://www.toyen.uio.ho/palmus/galleri/montre/english/x18.html  (Bothriolepis) http://www.amnh.org/Exhibition/Expedition/fossils/specimens/dunkleosteus.html   (Dunkleosteus) http://mdgekko.com/devonian/intro.html