CONTENTS 



Introduction ' 115 



DiNicHTHYiD Material ll6 



The Older Reconstructions of Dinichthys 117 



Nomenclature of Head and Body Plates and Sensory Canals 



IN THE ArTHRODIRA 122 



Description of the Armor of Dinichthys 127 



The Head Shield 127 



The Head Rooe 127 



The Side Plates of the Head ; 137 



Reconstruction of the Head Shield of Dinichthys 153 



The Body Carapace 159 



The Dorsal Shield 160 



The Ventral Shield 170 



The Connecting Plates Between the Dorsal and Ventral Shields 174 



The Connection Between the Head and the Body Carapace 179 



The Joint Between the Head and the Body 179 



The Relation Between the Gnathal Elements 183 



The Mechanism of the Mouth Movement 187 



The Complete Reconstruction of the Head and Body Carapace of Dinichthys 192 



Other Structures and Organs of Dinichthys 192 



The Primordial Neurocranium 192 



The Spinal Column and Fins 196 



The Gill Apparatus 199 



The BiOLOGY -of Dinichthys 202 



The Relationships and Systematic Position of the Arthrodira 202 



The Relationships Between the Arthrodira and Other Fish Groups 203 



The Arthrodira as an Independent Class " 207 



The Relationships of the Arthrodira to the Antiarcha (Asterolepida) 208 



The Systematic Position and Divisions of the Arthrodira 209 



Bibliography 213 



