VIII CONTENTS. 



Chawer IV. Systematic descriptions of genera and species — Continued. Page. 

 Review of the species of Laramie Ceratopsia — Continued. 



Genera and species described by Marsh and Hatcher, cheifly from Converse County, Wyo. — Continued. 

 Triceratops — Continued. 



T. calicornis 138 



Locality 138 



Original description 138 



Description of type 138 



T. obtusus 140 



T. brevicornus 141 



Locality and horizon 141 



Description of type 141 



Principal measurements 142 



Sterrholophus 143 



S. flabellatus 143 



Original description 143 



Locality and horizon 144 



Characters of skull 145 



Diceratops 149 



D. hatcheri 149 



Torosaurus 149 



T. latus 150 



Locality 150 



Original description 150 



Description of the type 151 



Principal measurements 152 



T. gladius 152 



Nodosaurus 155 



N . textilis 155 



Part II. Phylogeny, Taxonomy, Distribution, Habits, and Environment of the Ceratopsia, 



by R. S. Lull. 



Generic and specific summary 161 



General discussion of the phylogeny .' 161 



Revision of genera 162 



The Monoclonius-Triceratops phylum 162 



Monoclonius 162 



Centrosaurus 162 



Agathaumas 162 



Diceratops .' 163 



Triceratops 164 



The Ceratops-Torosaurus phylum 165 



Ceratops 165 



Torosaurus ] 65 



Eliminated genera 166 



Claorhynchus ; 166 



Dysganus 166 



Manospondylus 166 



Polyonax 166 



Stegoceras 166 



Sterrholophus 166 



Revision of species 167 



The Monoclonius-Triceratops phylum _ 167 



Monoclonius crassus 167 



M. dawsoni 167 



M. sphenocerus 167 



Centrosaurus apertus 168 



Agathaumas syl vestris 168 



Diceratops hatcheri ! " 168 



Triceratops (Ceratops) horridus 168 



T. prorsus 168 



T. brevicornus 169 



T. serratus 169 



T. (Bison, Ceratops) alticornis 170 



