554 



INDEX 



Physa, 247. 



Physalia, 475. 



Pigeons (Charadriiformes), 389. 



Pilsbry, H. A., 115. 



Piltdown man (Eoanthropus), 439. 



Pinnipedia, 402. 



Pisces, 182, 340, 342-357, 431, 467- 



Pisiform, 332. 



Pistils, 77. 



Pithecanthropus erectus, 438. 



Placentals, 397, 398-414; see Artio- 



dactyla ; Carnivora ; Chiroptera ; 



Edentata ; Insectivora ; Mystaco- 



ceti ; Odontoceti ; Perissodactyla ; 



Primates ; Proboscidea ; Rodentia ; 



Sirenia. 



Planarian, 180. 

 Planesticus migratorius propinquus, 



394- 



Plankton, 474, 477. 

 Plant-breeding, 60-6 1 ; green, 31; 



see also Chlorophyll. 

 Plasm, 17, 67, 115, 124, 132. 

 Plasma, of blood, 25. 

 Plasmodium, 190, 203, 204. 

 Plastron, 368. 

 Plathemis, 270. 

 Platyhelminthes, 180, 229^-232; see 



Cestoda; Temnocephaloidea ; Tre- 



matoda ; Turbellaria. 

 Platyrrhine, 409. 

 Plecoptera (Ephemeroidea) (Per- 



loidea), 269. 

 Pleistocene Epoch, 148, 381, 418, 427, 



428, 440. 



Plesiosaur, 365, 366, 369. 

 Pliocene Epoch, 148, 418. 

 Pliohippus, 418. 

 Polariscope, 480. 

 Pollen, 77. 



Polychsetae, 237, 238-239, 241. 

 Polyembryony, 38, 409; see also 



Generation. 

 Polyergus, 305, 306. 

 Polymorphism, 299. 

 Polyp, 40. 

 Polypeptids, 8. 

 Polyphemus moths, 289. 

 Polyphyletic organisms, 179. 



Polypterus, 345, 346. 



Polyxenus, 265. 



Pomolobus, 353. 



Popular Science Monthly, 163, 529. 



Population, Malthus on, 499. 



Porana cockerelli, 159. 



Porifera, 180, 207-209, 225. 



Portheus (Hypsodon), 348. 



Potamochaerus porcus, 410. 



Poulton, C. B., 1 14. 



Powell, Major, 529. 



Pratt, H. S., 242, 341. 



Primates, 409-410, 416, 433. 



Priority, 174. 



Proboscidea, 414, 425. 



Prochordata, 182, 320-326; see 

 Amphioxus ; Balanoglossus ; Tuni- 

 cata. 



Procyonidae, 402. 



Proellariiformes, 385. 



Proglottids, 231. 



Propagation ; see Generation. 



Propterus, 345. 



Proteins, 8; amino-acids of, 8; 

 complexity of, 8. 



Proterozoic Eras : Early Period, 148 ; 

 Late Period, 148. 



Proteus, 191. 



Prothallium, 78. 



Protophyta, 179, 186, 429. 



Protoplasm, 5-7, 37-38, 137; col- 

 loidal nature of, 9; complexity 

 of atoms of, 6 ; composition of, 5 ; 

 continuity of life of, 17; in- 

 stability of atoms of, 6; retention 

 of identity of, 7; structure of, 6; 

 see also Life. 



Prototheria, 396-397. 



Protorthoptera, 313. 



Prototracheata, 255, 263-265. 



Protozoa, 13, 14, 16, 17, 73, 138, 

 179-180, 186-193, 235, 254, 429, 

 465, 477, 487, 489; vs. disease, 

 199-206; vs. heredity, 194-198. 



Protracheata (Prototracheata), 255, 

 263-265. 



Protura, 267-268. 



Przewalski, 421. 



Pseudopodia, 29, 191. 



