xvi PRIMARY FACTORS OF ORGANIC EVOLUTION. 



PAGE 



Fig. 97. Psittacotherium multifragtim Cope, mandibular ra- 

 mus 329 



98. Diagrammatic representations of horizontal sections 



of tricuspidate molars of both jaws in mutual rela- 

 tion 333 



99. Deltatheriumfundaminis Cope, fragmentary skull . 336 



100. Centetes ecaudatus, skull and molars 337 



loi. Inferior molar crowns representing transition from 



the simple to the quadritubercular 338 



102. Stypholophus whitice Cope ; apposition of inferior 



and superior molars 339 



103. Cynodiciis geismariatitts Co'pe ; skull ..... 341 



104. Aeltirodon stTvus Leidy; coadaptation of crowns of 



superior and inferior molars in mastination . . 342 



105. Smilodon neogatis Lund ; skull 344 



106. Sections of crowns of molars of Ungulata .... 345 



107. Castoro'ides ohioensis Foster ; skull 347 



108. Castoro'ides ohioensis Foster ; skull from below . 350 



109. Ischyromys typtis Leidy ; cranium and mandible . . 351 

 no. Balana f?tyslicetus ; fore limb 353 



111. Feet of Amblypoda 354 



112. Feet of Proterotheriidae 358 



113. Dorsal vertebrae of merospondylous fishes .... 370 



114. WeviehraX column ol E)yops rnegacephalus CoY>e . 371 

 1 14^ Sleeve of coat 371 



115. Metatoceras cavatiformis Hyatt 406 



116. Do 407 



117. Temnochihis crassus 407 



118. Aletacoceras dtthiitvi Hyatt 408 



119. Hyatt on Cephalopoda 410 



120. Diagram explanatory of Diplogenesis 441 



