INDEX OF SUBJECTS 



335 



Pliallusia, 288. 



Pharmacology, 136. 



Phascolosoma, 25. 



Phosphorus, effect on Chick, 132 ; 

 necessity of, 141. 



Physa, crossed polar furrows, 46 ; 

 effect of fertilization, 250. 



Phvsico-chemical responses to stimuli, 

 285. 



Physiological zero, see Temperature, 

 minimum. 



Physiologically balanced solutions, 

 136. 



Physiology of development, 13 ; 

 physiological laws, 13, 298. 



Pigment, change of position in iso- 

 lated blastomeres of Frog, 53 ; 

 of Frog's egg, 79 ; disappearance 

 of, in Frog's egg, 80, 163 ; in 

 Fiinduli's, in darkness, 94 ; with- 

 out oxygen, 111, 114 ; distributed 

 through cell-body (gray degenera- 

 tion), 135; of secondary mesen- 

 chyme in Pluteus, 144 ; without 

 magnesium, 148; without calcium, 

 150 ; in neutral media, 151 ; of 

 Strongylocentrotus, 183-185; function 

 in gastrulation, 184, 192 ; of Den- 

 tal him, 222 ; of Cynthia, 230 sqq., 

 250. 



Pilidium, 205-207. 



Pilocarpine, 131. 



Pineal vesicles, inner wall of, split 

 in Lacertilia, 9. 



Pisces, egg-axis and embryonic axes, 

 178 ; half-blastoineres, 178 ; in- 

 juries to lip of blastopore, 178. 



Placenta, of Mammals, 7. 



Placenta! Mammals, segmentation, 

 24. 



Planorbis, segmentation in. 25 ; 

 crossed polar furrows, 46 ; light 

 of various colours, 94. 



Plant, division of cells, 41 ; absorp- 

 tion of water by, 58. 



Planula, nematocysts in, 3 ; from 

 blastula by unequal growth, 6 ; 

 from isolated blastomeres, 181 ; 

 giant, from fused blastulae, 202. 



Plate, medullary, see Medullary ; 

 plate, white, in inverted eggs, 

 85. 

 Platyhelmia, excretory tubules of, 



6 ; segmentation, 54. 

 Pluteus, in light of various colours, 

 96 ; ciliary movement of, 135 ; 

 effect of potassium, sodium, 

 lithium, 137 ; necessity of various 

 elements for, 142 sqq. ; partial, 

 194-196, 199, 200; hybrid, 258- 



262 ; arms of, dependent on 

 skeleton, 138, 144, 150, 195, 275; 

 growth rate of arms, 70, 71. 



Podarke, crossed polar furrows, 46. 



Pole cells, see Teloblast. 



Polar areas, in Frog's eggs exposed 

 to electric currents, and in other 

 structures, 92, 93 ; bodies, asters 

 of same size in, 31 ; in Asmris ni- 

 yrovenosa, 33 ; in Callidina, 34 ; 

 division, violate Hertwig's rule, 

 34 ; furrows, see Furrows ; lobe, see 

 Lobe ; nuclei, see Nucleus ; rings, 

 251. 



Polarity of Echinoid egg, 183 ; see 

 also Egg-axis. 



Polarization, meridional, in Frog's 

 egg, 83 ; of egg-particles, 281, 

 286. 



Polyaster, 128. 



Polyclads, 25 



Polychaeta, influence of gravity on 

 eggs, 78 ; pressure experiments, 

 39, 213. 



Polyspermy, pathological, 107 ; due 

 to poisons, 128; irregular distribu- 

 tion of chromosomes in, 253, 264, 

 265. 



Polyzoa, 22. 



Position, changes of position in 

 development, 3 : Davenport's cata- 

 logue of, 4 sqq. ; fate a function of, 

 188, 282. 



Post-generation of missing half- em- 

 bryo in Frog, 161, 162; denied by 

 Hertwig and Morgan, 170, 171; 

 confirmed by Endres, 171. 



Post-trochal region, 224. 



Potassium bichromate, 94 ; bromide, 

 123, 132; nitrate, 123; sulphate, 

 123 ; iodide, 132 ; chloride, 123, 

 133 ; cyanide, prolongs life, 131, 

 132 ; larvae of Echinoids, 137, 146 ; 

 necessity of, 146. 



Potentialities, altered by chemical 

 reagents, 140 ; limitation of, 175, 

 176, 180, 181, 191, 194, 201, 204, 

 242-244, 246, 277, 281, 284, 286; 

 due to lack of material, 182, 194, 

 201, 225, 242, 281, 291; due to 

 lack of specific material, 180, 201, 

 217, 225, 242, 243, 281, 291. 



Practical concept of freedom, 289. 



Predetermination of embryonic axes, 

 see Embryonic axes ; physico- 

 chemical, 285. 



Prediction, the function of science, 

 299. 



Preformation of organ-forming sub- 

 stances, 207, 227, 241, 286. 



