427 



Sirenia, 312, 314, 325 

 Sirenidse, 229 

 Siren ladertina, 229 

 Siricidae, 175 

 Skunks, 360 

 Sloths, 324 

 Slugs, 83 

 Smolt, 212 

 Snails, 83 

 Snipes, 291 

 Song of birds, 277 

 Sorex palustris, 366 



personal us, 366 

 Soricidae, 366 

 Spermatozoon, 385 

 Sphargis coriacea, 252 

 Sphecina, 181 

 Sphendon punctatum, 238 

 Sphingidae, 170 

 Sphynx moth, 170 

 Spider, crab, 108 



ground, 106 



jumping, 108 



running, 108 

 Sponges, 10-16 

 Spongilla, 12 

 Spongin, 11 

 Spores, 4 

 Sporocyst, 36 



Sporotrichum globuliferum, 142 

 Sporozoa, 4 

 Sporulation, 3 

 Squamata, 239 

 Squid, 84, 85 

 Squirrels, 351 



flying, 352 

 Starfish, 50 

 Steganopodes, 284 

 Stegocephala, 228 

 Stegomyia, 4 



fasciata, 157 

 Stickleback fish, 216 

 Stilt, 291 

 Stimulus, 7 



Stomodeum, beginning of, 26 

 Stone flies, 128 

 Stork, 287 



Struggle for existence, 388 

 " Survival of the fittest," 388 

 Swallow-tailed butterflies, 172 



tiger, 172 



zebra, 172 

 Swallows, 304 

 Swan, 285 



Swift, 247, 300 



Sword-fish, 205, 216 



Symbiosis, definition of, 4 

 Hydra viridis and algoe, 21 

 hydractinea and crab, 25 

 pinnotheres, 76 

 sponges and crab, 14 



Syngamus trachcalis, 43 



Syrinx, 267 



Syrphida?, 161 



Syrphus flies, 161 



Tabanid^, 156 

 Taenia echinococcus, 39 



saginata, 38 



solium, 37 

 Tamandua, 324 

 Tamaus siriatus, 352 

 Tanagers, 304 

 Tapeworm, 37 

 Tapirs, 332 

 Tapirus terrestris, 332 

 Tasmanian marsupials, 321 

 Teidffi, 245 

 Teleostei, 211 

 Teleostomi, 209 

 Teredo, 81 

 Termites, 131 

 Termitophily, 132 

 Tern, 282, 283 

 Terrapins, 252 



mud, 253 

 Tessera, 26 

 Testudinidffi, 253 

 Tetrapneumones, 106 

 Thalessa, 176, 177 

 Thallassophryne, 204 

 Theridiida;, 107 

 Thermorpha, 256 

 Thermotropism, 7 

 Thigmotropism, 7 

 Thomisidff, 108' 

 Thrashers, 305 

 Thrushes, 305 

 Thysanura, 126 

 Ticks, 110 

 Tiger, 364 



Tinodera sinensis, 136 

 Tissues, differentiation of, 386 

 Tolypeutes, 325 

 Tortoises, 253 

 Tracker, 365 

 Tragulida^, 337 

 Tree-frogs, 234 



