INDEX 



229 



Setae, 43, 48. 



Sexual selection, 174. 



Shark, 121. 



Silkworm, 84, 86, 95. 



Silver scale, 83. 



Siphon, 101. 



Siphonoptera, 82. 



Skeleton, of bird, 152; cat, 188; 



frog, 131; of fish, 113: chart of, 



218. 

 Skull, mammalian, 194. 

 Slipper animalcule, 13. 

 Sloth, 199. 

 Slug, 105. 

 Snail, 105. 

 Soil, 48. 



Sparrow, 182; English, 170. 

 Specialization, 20, 27, 66, 210. 

 Species, 8. 

 Spermary, 25, 27. 

 Spicule, 18.. 

 Spider, 94. 

 Spiracle, 77, 87. 

 Sponges, 17, 125; glass, 19; horny, 



19; limy, 19. 

 Sports, 148, 224. 

 Squash bug, 93, 95. 

 Squid, 106. 

 Stickleback, 119. 

 Struggle to live, 147. 

 Study, comparative, 82, 149, 223. 

 Sun energy, 2. 

 Sunlight, 2. 

 Survival of fittest, 147. 



Tadpole, 126, 134. 



Tapeworm, 49. 

 Tarantula, 94. 

 Teeth, of frog, 130. 

 Terrapin, 143, 144. 

 Toad, 137. 



Tortoise, 140, 143, 144. 

 Trap-door spider, 94. 

 Tube feet, 35. 

 Tumble bug, 90, 91. 

 Turtle, 140, 143, 144. 



Umbo, 98. 

 Ungulate, 212. 



Vacuole, 11, 12, 14. 

 Vampire, 203. 

 Variation, 147. 

 Variety, 8. 



Venomous snakes, 143. 

 Vent, 42. 

 Ventral, 43. 

 Vermes, 9, 125. 

 Vertebrates, 9, 125. 

 Vertebrate skeletons, 218. 

 Viscera, of bird, 163. 



Warning sound, 147. 



Wasps, digging, 89. 



Weevil, 90, 91, 96. 



Whale, 208. 



Wings, of grasshopper, 67 : 



bird, 153, 158. 

 Woodpecker, 180. 

 Worms, 42. 



Zoology defined, 1. 

 Zoophytes, 33. 



of 



