INDEX 



447 



phloem, 65. 



phosphorescent organs, 336. 



phosphorus, 22, 71. 



photosynthesis, 30, 31. 



phyla, 226. 



phyllodes, 280, 



Phyllopteryx eques, 341, Fig. 174. 



phylogenetic tree, 229. 



phylogeny, 229. 



,, and classification, 230, 

 231, Fig. 87. 



,. ,, ontogeny, 265, 279, 



Fig. 131. 



,, Erasmus Darwin on, 372. 

 physical basis of life, 7. 



,, conditions of earth, changes 



in, 327. 

 physiological selection, 418. 



unit, the cell, 68. 



Phytoflagellata, colony formation, 40, 



42. 

 ,, evolution of sex, 89 



91. 



Pierinae, 345. 

 pig, feet, 241, Fig. 98. 

 pineal eyes, 258260, Figs. 114116. 



gland, 11, 260. 

 pin-eyed flowers, 356. 

 pistil, 106. t 



Pisum sativum, Tarilties, 196. 

 pitcher plants, 262. 

 Pithecanthropus er^ctus, 423. 

 pituitary body, 408. 

 placenta, 270. 

 placental mammafe, appearance of, 



302. 



Plagianthus bctuliims, 417. 

 Plagiaulacidse, 302g 

 Plagiaulax, 302, 1% 148. 

 Planema poggei, 346. 

 plankton, 322. 

 plants, compared with animals, 34, 35. 



dispersal of, 321. 

 plasma, 51. 

 plasmodia, 67. 

 plasmogamy, 128. 

 plasticity of organisms, 335. 

 plastids," 32. > 



plastogamy, 128. 

 Platypus (see Ornithorhynchus). 

 Pleistocene Epoch, 284. 

 plerome, 50. 



Plesiosauria, 236, 244, 297. 

 Plesiosaurn* macrocephaltts, Fig. HI. 

 Pliny, 262. 

 Pliocene Epoch, 284. 

 Pliohippus, 310, 311, Figs. 153, 158. 



ploughshare bone, 305. 



plumage of birds, 349. 



plumcots, 204. 



pluteus larvae, 275, 276, Fig. 127. 



polar bodies, 133, 135, 139, 145, Figs. 



35, 65, 68. 



pole-cell, in insect egg, 130. 

 pollen, collection of, 355. 

 grains, 106, 107. 

 ,, sacs, 107. 

 tube, 108. 

 pollination, 110, 111. 



,, adaptations for, 351 363. 

 pollinia, 361. 



polyanthus, pollination, 356. 

 polydactylism, 149. 

 polymorphic colony, 119. 

 polymorphism in Papilio, 346, Fig; 



177. 



polype, fresh water (see Hydra). 

 Polypodium, archegonium, Fig. 52. 

 Polyzoa, dispersal, 327. 

 population, Buffon on, 368. 



Charles Darwin on, 386. 

 Lamarck on, 381. 

 Wallace on, 389. 

 porpoises, convergence in, 248. 

 Portunus, 247, Fi<r. 102. 



,, larva, Fig. 128. 

 postaxial, 238. 

 potential energy, 7. 

 Poulton, E. B., 336, 337, 346. 

 preaxial, 238. 



Pre-Cainbrian Epoch, 284, 285. 

 pre-formation in development, 163. 

 prehension, organs of, 256. 

 prepotency, 353, 358. 

 presence or absence hypothesis, 207. 

 Primary Era, 284, 285. 

 Primates, 301, 303. 

 primordia, in germ plasm, 206. 

 primordial germ cells, 113 (see alsc 



germ cells, origin). 

 utricle, 62, 95. 



Primula, fertilization, 356 358. 

 priority in nomenclature, 227. 

 Proboscidea, evolution, 312 314, 



Fig. 159. 

 proboscis, of bee, 354, Fig. 179. 



butterflies and moths, 



354. 



,, elephants, 256. 



,, insects, Erasmus Darwin 



on, 373. 

 mutual adaptation, 



414, 415. 

 procryptic colouration, 337342. 



