422 



PRINCIPLES OF ANIMAL BIOLOGY 



Purkinje, Johannes, 15 

 Pus, 127 

 Pylorus, 102 

 Pyridoxin, 111 



R 



Races, domestic, 366, 367 

 Radial canal, 175 

 Radial symmetry, 78 



in coelenterates, 79 

 Radicals, 35 

 Radius, 93 

 Rainfall, distribution of, in Michigan, 



314, 315 

 Ranges, continuity of, 311 



physical conditions of, 312, 313, 314, 

 315 



position of, 309 



size of, 310 

 Ray, John, 11 



taxonomy by, 245 

 Reactions, chemical, 33, 34 

 Recapitulation theory, 255, 256, 257 

 Recent, in geological time, 330, 335 

 Receptor, 144, 145, 146, 149 

 Recessive, 225 

 Rectum, 103 



Red corpuscles, 126, 127, 130 

 Reduction division, 194, 195 

 Reefs, 303 

 Reflex action, 146 

 Reflex arc, 144, 145, 146 

 Regeneration, of flatworms, 265 



of sponges, 262 

 Regulation, chemical, 152-158 

 Relicts, 309 



Renal corpuscle, 135, 136 

 Renal portal system, 126 

 Rennin, 104 

 Reproduction, 50, 159-176 



asexual, 159, 169-174, 176 



rate of, 288-290 



sexual, 159-168 

 Reproductive cycle, mammalian, 156-158 

 Reproductive tissue, 81, 85 

 Reptiles, evolution of, 335 

 Reptilia, 277, 279 

 Respiration, 46, 49, 114-119 



as an excretory process, 119 

 Respiratory systems, 114-116 



Responses to stimuli, 52, 53 

 Retina, 213 

 Rhinozoa, 247 

 Rhizopoda, 260 

 Riboflavin, 111 

 Ribs, 90 

 Rickets, 112 

 Rotifera, 275 



S 



Sacculina, homology, 350, 351 

 Sacrum, 91 

 Sagitta, 275 



X body in, 202 

 Salamander, 277 

 Saliva, 104 



and excretion, 139 

 Salivary gland, 101 

 Salmon, migration of, 318 

 Salts, 35, 36 



of protoplasm, 39, 40 

 Sand dollar, 267, 268 

 Sarcolemma, 95 

 Sarcoplasm, 95 

 Sargasso Sea, 303 

 Scaphiopus, distribution of, 309 

 Scaphopoda, 272 

 Scapula, 92, 93 

 Schultze, Max, 15, 19 

 Schwann, Theodor, 15 

 Science, definition of, 1 

 Scorpion, 274 

 Scyphozoa, 263, 264 

 Sea urchin, 89, 268 

 Secretin, 104 

 Secretion, 46, 50 

 Section, taxonomic, 248 

 Segmentation, 73, 194, 200, 201, 202 

 Selection, natural, 360-363 



criterion of advantage in, 362, 305 

 Self-fertilization, 180, 181 

 Seminal receptacle, of earthworm, 168 

 Seminal vesicle, 179 



of earthworm, 168 

 Semipermeable membrane, 43 

 Sense organs, in embryo, 213 

 Sensitive animals (Lamarck's classifica- 

 tion), 247 

 Sensory neuron, 144 



