456 



INDEX 



Polydactyly, 265, 266 



Polypterus, ribs, 71; pelvic girdle, 78 



Pongo, 189 



Porifera, 2S, 130 



Portuguese man-of-war, 23 



Prawn, deep-sea, 217, 237 



Precipitin tests, 96 



Prehensile appendages, for climbing, 



222; of primates, 191; for handling 



objects, 194; effect on evolution of 



primates, 196 

 Prenatal influence, 7 

 Primates, characteristics of, 187; 



classification of, 188; effects of ter- 

 restrial life on, 195 

 Primitive man, 3 

 Primordial germ cells, 292 

 Prjevalsky horse, 352 

 Proboscidea, 164 



Procamelus, skull, feet and teeth, 185 

 Proctodaeum, 48 

 Pronephric tubule, 65 

 Pronephros, 66 

 Pronuclei, 297 



Proserpinaca palustris, leaves of, 390 

 Protective adaptations, 234 

 Protective coloration, 10, 242 

 Proterozoic, 124; fossils of, 129; 



change of climate during, 248 

 Proteus anguinus, 224 

 Protohippus, 181, 183 

 Protoplasm, 29 

 Prototheria, 102, 157, 159 

 Protozoa, 28, 32, 33, 130, 131; clones 



in, 356; symbiosis with termites, 240 

 Protylopus, skull, feet and teeth, 185 

 Psychological variations, 267 

 Psychozoic, 122 

 Pteridophyta, 28 

 Pterodactyl, 153, 229, 232 

 Pteropus, 227 

 Pterosaurs, 230 

 Pterygoquadrate, 54, 73; of elasmo- 



branch, 58 

 Pterygota, 136 

 Pure lines, 35^; equivalents of, 355; 



of wheat, 356; selection in, 356; as 



limits of selection, 357 

 Pytonius, 151 



Quadroon, 362 

 Quaternary, 122 

 Quinto Porto, 3^7 



Rabbits, 219; inheritance of color in, 

 321; inheritance of ear length in, 

 318; Guyer and Smith's experi- 

 ments with, 421 



Recapitulation theory, 110 



Recessive, 279, in back-cross, 285 



Reciprocal cross, 308 



Reduction division, 294 



Regression, filial, Galton's law of, 

 355, 401 



Relationship, significance of, 105; of 

 individuals, 106; of species, 107; 

 of organism and environment, 261 



Reproduction, 90; of cells, 99; of in- 

 dividuals, 101; accessory functions 

 of, 101; in unicellular organisms, 

 100, 272, 273; in multicellular or- 

 ganisms, 273; as passive protec- 

 tion, 234; and change of environ- 

 ment, 250 



Reptiles, cursorial, 219; in vertebrate 

 evolution, 152; of Mesozoic, 153 



Reptilia, 37 



Rhacophorus, 229 



Rhamphorhynchus phyllurus, 232 



Ribs, 71, 72 



Rickets, 431, 434 



Rignano, 424 



Rocks, formation of, 119 



Rocky Mountains, 120, 257 



Roses, 345 



Rotatoria, 28, 137; elimination of 

 male in, 329 



Roux, 291, 408 



Sacrum, 72; human, 73 



Saint-Hilaire, 9, 12 



Salamander, blind, 224; cell from 



peritoneum, 290 

 Saldidae, 254 

 Saltatory adaptations, 219 

 Sambo, 363 

 Sandstone, 120 . 

 San Jose Scale, 251 

 Sauripterus taylori, pectoral girdle 



and fin, 75 

 Scale, San Jose, 251 

 Scales, 83 

 Scansorial adaptations, 222; and 



adaptive radiation, 253 

 Scaphyrhynchus, pelvic girdle of, 78 

 Schaffner, 336 

 Schistosotna haematobium, 23 



