INDEX 



Placenta, 



hormones of, 262, 263 



human, 276 



in nutrition, 258 



permeability of, 277 



transfer across, 2 58, 276, 277 

 Planarian, regeneration in, 230 

 Plasticity (see Labile organization) 

 Pluteus larva, 28 

 Polar bodies, 305 

 Polarity, 



of frog egg, 56 



of limb disk, 98 



in regeneration, 231, 233 



of sea urchin egg, 27 

 Posterior cardinal vein, 174, 178 



in chick, 72-hr., 216 



in frog, 137 

 Posterior intestinal portal, 19 1 

 Potassium sulfocyanide, on sea urchin 



egg, 34, 35 

 Potency, defined, 70 

 Potencies, 



of gastrular ectoderm, 72, 74 



limitation of, 76 



of neurula ectoderm, 76 



restriction of, 107 

 Preformation theory, 4, 27 

 Pregnancy, 



effect of, 



on corpus luteum, 260 

 on ovarian cycle, 261 



effect of Vitamin E on, 264 



tests for, 23 

 Premature birth, 288, 289 

 Presumptive epidermis, in amphibian, 60, 



64 

 Presumptive neural plate, 60, 64 



human, 269 

 Presumptive notochord, in amphibian, 60, 



64 

 Presumptive values, 



of amphibian gastrula, 58, 60 



definition of, 61 



of sea urchin egg, 27 

 Primitive groove, 207, 209 

 Primitive streak, 



in chick, 206, 207, 208, 209, 210, 211 



compared with blastopore, 80 



in human, 268, 269 



organizer action of, 87. 82 



327 



Progesterone, action of, on uterus, 260, 



261, 263 

 Progressive determination, 107 

 Progressive differentiation, 107 



within a field, 104 

 Progressive self-differentiation, 107 

 Pronephric duct, 



in chick, 194, 197 



in frog, 137 

 Pronephric tubule, 



in chick, 194, 197 



in frog embryo, 137 

 Pronephros, 70 



in chick, 194, 197 



in frog, 130, 137, 138 



in human, 279 

 Prosencephalon (see also Forebrain), 



in chick, 213 



in frog, 133 

 Proteins, for growth, 251 

 Pulmonary arch (sixth aortic arch), 183 

 Pulmonary artery, origin of, 179 



Quantitative theory, 



of organization in sea urchins, 39-41 



of organizer, 90 



in regeneration, 235, 236 



Radioactive phosphorus, 230 

 Rana sylvatica, 



breeding habits of, 112 



sex reversal in, 302 

 Rate of development, in relation to tem- 

 perature, 1 1 1 

 Rathke's pouch, in chick, 



48-hr., 217, 218 



72-hr., 224 

 Rectum, 191 

 Red blood corpuscles, rate of formation 



of, 229 

 Reduplication, 249 

 Reflexes, 



in frog, 132 



in human fetus, 280, 283, 284, 285 

 Regeneration, 



in frog, 231,232 



inhydroids, 231,232 



of nerve fiber, 145, 146 



origin of cells in, 236, 237 



in planarian, 230 



role of nerves in, 239, 240 



role of skin in, 241 



