INDEX 



391 



Scales 



Dermal, 110 

 Mammal, 115 

 Reptile, 113 

 Scapula, 158, 163 

 Sclerotic layer, 308 

 Scrotum, 267 



Sebaceous glands, 117, 118, 330 

 Sedimentary Rocks, 330 

 Segmentation cavity, 21 

 Sella turcica, 138 

 Semen, 267 



Semicircular canals, 309 

 Sex differentiation, 268 

 Sex glands, 319 

 Seymouria, 58, 134, 346 

 Sinanthropus, 353 

 Sirenia, 90 

 Skates. 37, 38 

 Skeleton, development, 171 

 Skin, 107 



Human, 122 

 Skull 



Dermal bones, 131 

 Development, 125 

 Evolution, 134 

 Fenestrae, 135 

 Reptile, 346 

 Snakes, 62, 63 

 Somatopleure, 195 

 Specialized, Def., 6 

 Sphenodon, 61 



Spinal accessory nerve, 298 

 Spinal cord, structure, 277 

 Spinal nerves, 277 

 Spiracle, 39, 144 

 Spiral valve, 39, 201 

 Splanchnopleure, 195 

 Spleen, 195 

 Stegocephalia, 50, 345 

 Dermal plates, 110 

 Pelvis, 164 

 Skull, 134 

 Vertebrae, 149 

 Sternum, 154 

 Stomach 

 Development, 193 

 Modifications, 199 

 Strata, formation, 331 

 Sweat glands, 118, 123 

 Swim bladder, 40, 45, 211 

 Sylvius, aqueduct of, 292 



Sympathetic system, 287 

 Synapsida, 60 

 Synotic tectum, 126 

 Systematic, Def., 97 

 Systemic, Def., 97 



Taste buds, 302 

 Teeth, 139 ff. 

 Teleostei, 42, 344 

 Teleostomi, 39 

 Tendons, 178 

 Terminal nerve, 295 

 Testes 



Descent, 267 



Function, 319 

 Therapsida, 59 



Jaws, 131 



Skull, 136 

 Theromorpha, 59, 60 



Jaws, 131 



Skull, 136 

 Thinopus, 160, 161 

 Thorax, 155 

 Thvmus, 207, 317 

 Thyroid, 33, 207, 316 

 Time table, geological, 335 

 Tongue, 199 

 Trigeminal nerve, 297 

 Trochlear nerve, 296 

 Turbinal bones, 303 

 Tunicates, 13 

 Turtles, 57 



Skull, 134 

 Twinning, 314 



Unguligrade, 169 



Ureter, 255 



Urethra, 257 



Urinogenital svstem, development, 



258 

 Urochordata, 13, 343 

 Urodela, 50 

 Uterus, 262 

 Utriculus, 310 



Vagina, 262 

 Vagus nerve, 298 

 Valves, of heart, 231 

 Vascular system 



Amphioxus, 19 



Development, 229 



Dogfish, 222 



