510 



INDEX 



physiological genetics, 5, 409 f. 

 physiological isolation, 296, 325 

 physiological mosaic, 193 

 piano-playing, 436 

 pigeons, thyroid-activity, 436 

 pigment, gradients, 381 

 pigment-cells, function and multi- 

 plication, 426 

 Pinnotheres, growth-gradient, 308 

 pituitary, 33, 179, 198 

 pituitary hormone, 198, 425 

 placode, 28, 31, 199 

 Planaria, apical region, inductive 

 capacity, 286 



biaxial regeneration, 285, 296 



cyclopia, 303, 349 



differential inhibition, 301 



differential susceptibility, 303 



growth-gradient, 367, 372, 422 



heteroplastic grafts, 165 



multiple heads, 299, 326 



narcotics, 285, 287, 301 



organiser, 165, 166, 167, 286 



range of dominance, 286, 287 



reduction, 368 



regeneration, 271, 273, 279, 308 



tail, 283, 305 

 Planorhis, shell-form, 81 

 plasticity, 44, 45, 46 f., 47, 94 



regeneration-buds, 272, 273 

 Platycnemis, activating centre, 170, 171 



chemo-differentiation, 127 



inside-out, 252, 253 



nuclear equality, 88 



regulation, 127, 128 

 Pleiirodeles, labile determination, 136, 



137 



neural crest, 393 



organiser, heteroplastic grafts, 142 

 pluteus, arms, 174 



skeleton, 174, 181, 405 

 polar body, 15, 119 

 polar lobe, Chaetopteriis, 113, 171, 219 



Dentaliio7i, 109, iio, 117, 120, 216 



Ilyanassa, 113, 121, 122 



Myzostoma, 113 

 polarity, 35 f., 56, 60 f., 70, 83, 123, 

 279, 312, 331 



blastoderm, bird, 161 f. 



epidermis, cilia-beat, 235, 488 



frog's egg, 14 



Fuciis, 61 



Hydra, 164, 280 



limb-field, 224, 358 



polarity, organ-fields, 229, 233, 243? 



359 



of organiser, 149 



sea-urchin, 60, 105, 218, 323, 337 

 polarity-gradient, 64 

 pole-plasms, Clepsine, 114, 117, 119 



Tubifex, 113, 171, 216 

 Polychaetes, organisers, 165 f. 



polar lobes, 113 f. 

 Polydactyly, 262 

 polyembryony, 328 f. 

 polyspermy, frog's egg, 131 

 Polyzoa, polyembryony, 328 

 position, and cell-fate, 281 

 positive and negative determination, 



216 

 post-generation, 91 

 post-trochal region, Dejitaliiim, no, 



III, 112 

 potassium, effects of, 331 

 potential difference, 308 

 precursor substances, 412 

 preformation, 2 f., 58 



organ-forming substances, 117 

 prefunctional period, 34, 418 f. 

 prelocalisation, organ-forming sub- 

 stances, 117 f, 

 presumptive regions, 21 f., 23, 24, 43 

 primitive streak, 159 f. 

 primordial germ-cells, 254, 263 

 proctodaeum, 31 

 pronephric duct, 32 

 pronephros, induction, 50, 135, 152,192 



inductive capacity, 145, 193 

 proportions, change of, 421 

 prototroch. Patella, 116 

 Psammechiniis, bilateral symmetry, 69 

 Psoitis, dorso-ventral axis, 69 

 psychological changes, at metamor- 

 phosis, 396 



rabbit, tissues explanted, 201 

 Rana {see also frog), balancer- induction 

 in Triton, 177 

 blood, mosaic development, 198 

 ear-vesicle and capsule-induction, 

 175 

 Rana cateshiana, lens-differentiation, 



189 

 Ratia escidenta, egg-axis, 14 

 eye-determination, 245, 246 

 lens-differentiation, 184, 186 

 lens-fibres, 190 

 sucker formed on Triton host, 143 



