INDEX 



421 



I'MToiital rare, relation of, to birtli 



stages, 192 

 Parthenogenosis, 164-166 



artificial, 165 

 Parts, relation of, to whole, 64, 65 

 Pectoral girdle, 92, 93 

 Peking man, 345 

 Pelecypoda, 271, 272 

 Pellagra, 111 

 Pellicle, 25, 27 

 Pelvic girdle, 92, 93 

 Penaeus, biogenetic law in, 256 

 Penis, 179, 180 

 Ponnsylvanian, 330, 332, 335 

 Pepsin, 104 

 Pepsinogen, 104 



Period, in paleontology, 329, 330 

 Peripheral nervous system, 142, 143 

 Perisarc, 172, 173 

 Peritoneum, 80, 81 

 Permian, 330, 332, 335 

 Petrifaction, 327, 328 

 Phalanges, 93 



Pharynx, of earthworm, 101, 102 

 of flatworm, 102 

 of frog, 102 

 Phoronidea, 275 

 Photosynthesis, 46, 47 

 Phylum, 247, 248 

 Physalia, 175, 176 

 Phvsics, 30-38 



Physiology, 16, 20, 22, 39-53 

 Piltdown man, 345 

 Pineal body, 153, 156 

 Pisces, 277, 279 

 Pithecanthropus, 344, 345 

 Pituitary, 153, 155, 157 



migration stimulated by. 318 

 Placenta, 183, 184, 185 

 Planaria, 265, 266 

 Plant communities, 292 

 Plants, as food for animals, 47, 48 

 Planula, 173, 174 

 Plasma, 126 

 Plasmodroma, 260 

 Plastid, 26, 27 



Platelets, blood, 126, 127, 130 

 Plato, 4 



Platyhelminthes, 264-266 

 Pleistocene, 330, 335 



Pleodorina, gamet(>s in, 161, 162 



sterile cells in, 70, 71-73, 75 

 Pliny, 5, 6 

 Pliocene, 330, 335 

 Pliohippiis, 342 



feet of, 341 

 Pneumatophore, 174, 175 

 Podophrya, 260 

 Polar body, 160, 194, 197, 198 

 Polarity, 28 

 Polocyte, 197, 198 

 Polychaeta, 270 

 Polymorphism, 174, 175 



in coelenterates, 263 

 Polyneuritis, 111 

 Polyp, 172, 173, 262 

 Polysaccharide, 40 

 Ponds, 294-296 



vegetation in, 294, 295 

 Porifera, 261, 262 



Portal system, 126 



Portuguese man-of-war, 175, 176 



Potato beetle, distribution of, 317 



Potential energy, 37 



Precocial birds, 190 



Precoracoid, 92, 93 



Prehistoric man, 344-348 

 American, 348 



Primates, evolution of, 335 



Priority, law of, 249 



Precocious vertebrae, 92 



Prophase, 56, 57 



Prosecretin, 106 



Proteins, 40, 41 



Proterospongia, gregaloid colony in, 68, 

 69 



Proterozoic, 330 



Prothrombase, 112, 130 



Proton, 31 



Protonephridium, 134 



Protoplasm, movement of, 51-53 

 organization of, 23-29 

 structure of, 42, 43 



Protozoa, 259-262 



essential to termites, 287, 288 



Protozoologist, 257 



Pseudopodia, 24, 51 



Ptyalin, 104 



Pubis, 92, 93 



Pulmonary circulation, 124 



Pupa, 215, 216 



