INDEX 



Somatic layer of mesoderm, 70 



in frog embryo, 137 

 Somatopleure, in chick, 175, 201 

 Somites, 71 



in chick, 213, 226 



development of, 193, 195 



in frog, 130, 137 



in human, 274, 275 



origin of, 193, 195 



in pig, 27 1 

 Specificity of nerves, 149 

 Sperm, 



activity of, 45 



effect of Vitamin E on, 264 



length of life of, 51, 53 

 Spermatocyte, 305 

 Spinal cord, 



in frog embryo, 137 



internal differentiation of, 162 



regional differentiation of, 1 55 

 Spinal ganglia, 160 



of human, 271 



of pig, 271 

 Spiracle, of frog, 139 

 Splanchnic mesoderm, 70 



in chick, 200 



derivatives of, 200 



in frog, 137 



induction of, 200 



in heart formation. 177 

 Splanchnopleure, in chick, 175, 201, 218 

 Spleen, origin of, 200 

 Stationary state, in growth, 245 

 Stereotropism, 144 



Stimulation, of human fetus, 284, 2S5 

 Stimulus, for limb regeneration, 2-40, 241 

 Stomach, 



in human, 278 



of pig, 10-mm., 273 

 Stomodeum, 134, 135 



in chick, 218 

 Structural differentiation, 108 

 Suckers (see also Mucous gland). 130. 



131, 132 

 Suprarenal cortex (Adrenal cortex), 



androgen of, 277, 282 



of fetus. 277 

 Suprarenal gland (see Adrenal gland) 

 Swallowing, in human fetus. 285, 286 

 Sympathetic ganglia, origin of, 141, 142, 

 160 



329 



Syntrophoblast, 268 

 Systemic artery, origin of, 179 



Tadpole, 



metamorphosis of, 140 



structure of, 139, 140 

 Tail, in human, 280, 282 

 Tail bud, in chick, 48-hr., 222 

 Tail fold, 215,276 

 Telencephalon, 164, 165 



in chick, 



48-hr., 216, 220 

 72-hr., 223, 225 



in human, 282 



in pig, 271 

 Telolecithal egg, 204 

 Temperature, 



effect of, on rate of development, 111 



of incubation, 104 



limits of, 112 

 Testes, 



descent of, 287 



development of, 299, 300, 301 



in human, 282 

 Testosterone, effect of, 



on chick embryo, 300, 302 



on development, 277 

 Thalamus, 166 

 Thymus gland, 188 

 Thyroid, 187, 188 



in chick, 

 48-hr., 220 

 72-hr., 226 



effect of. on metamorphosis, 140 



in frog embryo, 136 



in human, 278, 280 

 Tissue culture, 



of heart, 177 



of intestinal epithelium, 191 



of lung epithelium, 191 



of neuroblasts, 143 

 Tongue. 187 

 Trachea. 188 

 Transplantation, 



of chick limb bud, 105 



of dorsal lip, 77, 78 



of eye, 95 



of gastrular ectoderm, 72, 74 



of heart field, 102 



of limb disk, 98 



of otocyst, 94 

 Trophoblast, 266 



