Index 



375 



Reversion, 322 

 Rhizopods, 212 

 Rotifers, 7, 4 2 > 2 34 

 Round-mouths, 9, 252 

 Rudimentary organs, 277 



SACCOPHORA, 62 



Sacculina, 48 



Sea-horse, parental care of, no 



Seasonal dimorphism, 314 



Segmentation, 195 



Sensations, 151 



Sex, 96 



Sexual reproduction, 186-188 



selection, 98 

 Shells of molluscs, 243 

 Shepherding, 119, 120 

 Shifts for a living, 46-66 

 Skunk, 55 



Snails and plants, 30 

 Snakes, 260-263 

 Social inheritance, 337-339 

 life of animals, 67-94 

 organism, 93, 94 



Societies, evolution of, 87 



Song of birds, 96 



Spencer, 297, 298 



Spermatozoon, 192, 193 



Sphex, 121 



Spiders, courtship of, 101-105 

 bird-catching, 36 



Sponges, n, 222 



Spongilla, 186 



Spring, biology of, 95. 9 6 



Starfish, 235 



ickleback, courtship of, 99 

 parental care of, 109, no, 122 



tinging-animals, n, 223-228 



toring, 120, 121 



truggle for existence, 32-45 



urrender of parts, 64-66 



ymbiosis, 69 



TAPEWORMS, 229 

 Termites, 24, 84-87 

 tissues, 179, 180 

 Tortoises, 263 

 Toxotes, 118 

 Trematoda, 229 

 Tunicates, 9, 250, 251 

 Turbellaria, 228 



VARIATION, 299 



Vertebrata, characters of, 19, 248, 



249 



Vital force, 19 

 Vivarium, 20, 21 

 Volvox, 187 



WALLACE, 296, 297 

 Warning colours, 55, 5 6 

 Weapons of animals, 34 

 Web of Life, 18-31 

 White Ants. See Termites 

 Worms, 10, n, 228-235 



YOLK, 195 



ZOOLOGY, history of, 35 2 -357 



THE END 



Printed ByR. & R. CLARK, Edinburgh 



