544 PRIMARY FACTORS OF ORGANIC EVOLUTION. 



Pike, 21. 



Pilsbry, 260. 



Pinnotheres holothuriae, 242. 



Pipilo eryihrofi/iihahnus, 52. 



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



Plagiaulacidae, 324, 345. 



Plagiaulas, 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. guadrilineatus 



D. & B., 68. 

 Polyprotodontia, 140, 143. 

 Polypterus, 89. 

 Polyzoa, 202. 

 Porifera, 80, 81. 

 Pouchet, 498. 

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



439. 449, 45i. 

 Pre-Caiboniferous 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. 



331, 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 sag 



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. 

 Ptenoplius ga7-rulus Smith, 73. 

 Pteridophyta, 77, 79. 

 Pterosauria, 115. 

 Ptilodus, 324. 



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

 Putorius ertiiineus, 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. 

 Quiscaliis pzirpiireus, 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; A'. 



clainata, 68 ; R. hexadaciyla, 68 ; A'. 



iemporaria, 64. 

 Ranidae, 65, 70, 71, 389. 

 Raphanus raphanistruin L., 227; R. 



sativus L., 227. 

 Recapitulation, 453, 492. 

 Reduction of digits, 309. 

 Regeneration, 455. 

 Reptiles, degeneracy of the eye of 



