Index 



883 



Pyrimidines, excretion of, 190 



in diet, 130 



requirements for, 123 

 Pyrophorus, luminescence in, 664 

 Pyrosoma, luminescence in, 665 

 Pyruvic acid, oxidation of, 269, 271 



Q.o, 342 



Quotient, respiratory, 274 



Radiation, absorption of heat from, 356 

 Raja clavata, equilibrium reception in, 517 

 Rana. See also Frogs. 

 Rana fusca, cutaneous vs. pulmonary res- 

 piration in, 212 

 Rana esculenta, cutaneous vs. pulmonary 



respiration in, 212 

 Rana temporaria, respiration in, 213 

 Rat, essential amino acids lor, 117 

 muscular action potentials from, 591 

 oxygen consumption of, 227 

 phonoreception in, 491 

 Ratio, U/P, 697 

 Reception of food, 147 

 Reciprocity law, 406 



determined from electrical measure 



ments, 425 

 in measurement of visual functions, 

 431 

 Red blood cells. See Erythrocytes. 

 Reflexes, conditioning of, 846 



ganglionic, in invertebrates, 812 

 Refractory period in synaptic transmission, 



800 

 Regulation, ionic, 80-84 

 mechanisms of, 90-94 

 responses to alterations in medium, 



84-90 

 See also Ionic regulation. 

 osmotic, 8, 14-20. See also Osmoregula- 

 tion. 

 Reissner's membrane, 475 

 Relaxation of muscle, 601 

 Relaxin, 748 

 Renin, 761 

 Rennin, 163 



Reproduction, hormones and, 740-756 

 Reproductive cycles, control of, 748 



factors influencing, 750 

 Reptiles, body temperature of, 358 

 erythrocytes in, 295 

 forebrain in, 836 

 hemoglobin content in, 295 

 kidney in, 48 

 melanophores in, 712 

 nitrogen excretion in, 195 

 osmoregulation in, 58 

 phonoreception in, 489 



Reptiles, respiratory characteristics of blood 

 of, 307 



respiratory control in, 257 



respiratory responses in, 266 



uricolytic enzymes in, 204, 205 

 Respiration and metabolism, 209-289 

 summary of, 277 



control of, in diving birds and mammals, 

 258 

 in molluscs, 263 



cutaneous, 211 



flight and, 261, 262 



gills in, 213 



in insects, 264 



in polychaetes, 262 



in Ttibifex, 262 



lungs in, 212, 217 



nervous control of, 830 



pulmonary, 212 



regulation of, 254-268 



skin in, 211 



temperature and, 261 



tracheae in, 222 



types of mechanisms for, 211-223 



See also Oxygen consumption. 

 Respiratory center, organization of, 830 

 Respiratory quotient, 274 

 factors affecting, 275 

 Respirometers, 224 

 Response, conditioned, 842 



neural basis for, 843 

 Retina, action potential of, 421 



effect of temperature on, 423 



activity of, optic nerve activity and, 423 



electrical activity in, 420 



in color vision, 438 



in compound eye, 387 



pigment of, hormonal control, 763 



vertebrate, structure of, 395 

 Retinenei, 410 



Rhabdom in compound eye, 387 

 Rheotaxis, 508 

 Rhodnius, developmental hormones in, 733 



experimental parabiosis and telobiosis in, 

 734 

 Rhodopsin, 395, 397, 410, 411 



phylogenetic origin of, 412 

 Rhythm, cardiac, 545 



diurnal, color change and, 687 



in nervous systems, 806, 807 



muscular, 605 

 Riboflavin, requirements of, 124 

 Rodents, water balance in, 59 

 Rondeletia, luminescence in, 662 

 Rotatoria, oxygen supply of, 211 

 RPH, 764 



R.Q. See Respiratory quotient. 

 Ruffini organs, 364 



Ruminants, cellulose digestion in, 172 

 Rutin, 130 



