544 PRIMARY FACTORS OF ORGANIC EVOLUTION. 



Pike, 21. 



Pilsbry, 260. 



Pinnotheres holothnrzae, 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. 



PolyDedates, 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, 

 33i. 332, 345- 360, 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 erminens, 50. 

 Pygopodidae, 123. 

 Pythonomorpha, 120. 

 Pyxicephalus, 71. 



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



294, 306, 326, 332, 360, 361, 467. 

 Quebec group, 413, 420. 

 Quenstedt, 189. 

 Quiscalns purpuretis, 52. 



Rabl Ruckard, 94. 



Raccoon pacing, 299. 



Rachitomi, 109, no, in, 372. 



Radiant energy, 484. 



Rana agilis Thomas, 68; R. catesbey- 



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



(lai)iata, 68; R. hexadactyla,6S>; R. 



tcii/poraria, 64. 

 Ranidae, 65, 70, 71, 389. 

 Rapkanus raphanistrum L., 227; R. 



sattz'us L., 227. 

 Recapitulation, 453, 492. 

 Reduction of digits, 309. 

 Regeneration, 455. 

 Reptiles, degeneracy of the eye of 



