LIST OF ILLUSTRATIONS. xv 



Fig. 62. Ostrea virginiana 264 



63. Diagrammatic representation of the segments of the 



leech 270 



64. Diagrammatic representation of the rings of a primi- 



tive crustacean 271 



65. Diagrams of hand of Crangon and of Astacus . . . 274 



66. Elbows of man and horse 280 



67. Elbow of horse . . 281 



68. Periptychus rhabdodon Cope, showing foot .... 288 



69. Hind foot of Poebrotherium labiatum Cope .... 290 



70. Hind foot of three-toed horse 290 



71. United first bones of two middle toes of deer-antelope 291 



72. Wrist-joints at distal extremity of fore arm . . . 292 



73. Elbow-joint of Crocuta maculata L 294 



74. Elbow-joint of chimpanzee 295 



75. Elbow -joint of Cervus elaphus 296 



76. Cervus canadensis in motion 297 



77. Cervus elaphus 298 



78. Diagram of carpus of a Taxeopod, of a diplarthrous 



ungulate 299 



79. Raccoon pacing 299 



80. Rhinocerus unicornis carpus 300 



81. Equus caballus fore foot 300 



82. Gazella dorcas 301 



83. Pes of Merychochcerus montanus and Bos taurus . . 307 



84. Anterior feet of primitive Ungulata 308 



85. Righ t posterior foot of Prothippus and Poebrotherium 310 



86. Manus of Artiodactyla 312 



87. Burrs on antlers of Cosoryx necatus Leidy .... 316 



88. Diagram of excursion of lower jaw in mastication . 320 



89. Cervus, molars 321 



90. Cusps of superior premolars and molars 322 



91. Two true molars of both jaws of a ruminant . . . 323 



92. Sections of superior molar teeth 323 



93. Chirox plicatus Cope, palate and molar teeth . . . 324 



94. Meniscoessus conquistus Cope, last two superior mo- 



lars 325 



95. Lemur collaris, dentition 326 



96. Esthonyx burmeisterii Cope, dentition 328 



