544 PRIMARY FACTORS OF ORGANIC EVOLUTION. 



Pike, 21. 



Pilsbry, 260. 



Pinnotheres holotkuriae, 242. 



Pipilo erythrophthalmus, 52. 



Pisces, 87, 95, 98, 192, 195. 



Plagiaulacidae, 324, 345. 



Plagiaulax, 142. 



Plant variation, 23. 



Plants, fossil, 77; evolution of, 515. 



Platidia, 178, 179. 



Platypus, 135. 



Plectognathi, 106, 107, 108. 



Plectospondyli, 106. 



Plesiosauria, 114, 121. 



Pleuracanthus, 372. 



Pleuronectidae, 238. 



Plicatula, 267. 



Pliny, 227. 



Pliocene, 387. 



Plistocene, 149, 168. 



Podopterygia, 100. 



Poebotheriidae, 302. 



Pollard, 89. 



Polygamy, 390. 



Polymastodon, 142. 



Polymastodontidae, 324. 



Polynesians, 154. 



Polypedates, 68 ; P. quadrilineatus 



D. & B., 68. 



Polyprotodontia, 140, 143. 

 Poiypterus, 89. 

 Polyzoa, 202. 

 Porifera, 80, 81. 

 Pouchet, 498. 

 Poulton, E. B., 230, 237, 381, 392, 393, 



439, 449, 461. 



Pre-Carboniferous age, 421. 

 Pressure, 286, 292, 295, 340, 405, 519. 

 Principle of improvement, 527. 

 Proal mastication, 318. 

 Proboscidia, 128, 132, 133, 136, 141,144, 



297, 305, 306, 309, 318, 321, 329, 330, 



33L 332, 345, 36o, 382, 519. 

 Procolophonina, 87. 88. 

 Procyonidae, 48. 

 Production of colors in lepidopterous 



pupae, 230. 

 Prognathism, 417. 

 Proportions of limbs and of their seg 



ments, 305. 

 Prorastomus, 330. 



Protective colors, 392. 

 Proteida, 109, no, in. 

 Proteles. 146. 

 Proterotherium, 359. 

 Proterotome mastication, 318. 

 Proteus, 242. 

 Prothallium, 455. 

 Prothippus, 149, 359. 

 Protodonta, 388. 

 Protophyta, 75, 76, 77, 172. 

 Protoplasm, composition of, 483. 

 Prototheria, 88, 324 360, 374. 

 Protozoa, 75, 79, 81, 83, 172, 219, 249, 



252, 505. 

 ProtozoOn, 459. 

 Psalidodect mastication, 318. 

 Pseudis, 71. 

 Pseudosauria, 109. 

 Pseudosuchia, 116. 

 Psittacotherium, 329, 346, 351. 

 Ptenophus garrulus Smith, 73. 

 Pteridophyta, 77, 79. 

 Pterosauria, 115. 

 Ptilodus, 324. 



Puerco, 139, 140, 141, 147, 150, 156, 403. 

 Putorius erntineus, 50. 

 Pygopodidae, 123. 

 Pythonomorpha, 120. 

 Pyxicephalus, 71. 



Quadrumana, 132, 133, 136, 143, 293, 



294, 3o6, 326, 332, 360, 361, 467. 

 Quebec group, 413, 420. 

 Quenstedt, 189. 

 Quiscalus purpureus, 52. 



Rabl RQckard, 94. 



Raccoon pacing, 299. 



Rachitomi, 109, no, in, 372. 



Radiant energy, 484. 



Rana agilis Thomas, 68 ; R. catesbey- 



ana, 68 ; R. chrysoprasina, 68 ; R. 



clamata, 68 ; R. hexadactyla, 68 ; R. 



temporaries, 64. 

 Ranidae, 65, 70, 71, 389. 

 Raphanus raphanistrum L., 227; R. 



sativus L., 227. 

 Recapitulation, 453, 492. 

 Reduction of digits, 309. 

 Regeneration, 455. 

 Reptiles, degeneracy of the eye of 



