INDEX 



257 



Sarcoptes scabei (illus.), 138. 



Scelophorus undulatus (illus.), 185. 



Scorpion (illus.), 134. 



Scyphozoa, 37 ; development of, 38. 



Sea-anemone, 40. 



Sea-cucumber (illus.), 143 ; regen- 

 eration of, 145. 



Sea-lily (illus.), 143. 



Sea-mat (illus.), 68. 



Sea-urchin (illus.), 141. 



Sea-squirt (illus.), 152. 



Sedentary life, effect of, 62. 



Segments, of worms, 55 ; of arthro- 

 pods, 94. 



Segmented worms, 55. 



Serpentes, 186. 



Serpent-star (illus.), 141. 



Serphus dilatatus (illus.), 122. 



Serpula (illus.), 62. 



Serpulids, 62. 



Seta, 55. 



Sexual reproduction, 32. 



Shark (illus.), 159. 



Shell-gland, 108. 



Shipworm, 75. 



Shrew, 234. 



Shrimp, fairy, 94 ; opossum (illus.), 

 100. 



Silk-moth (illus.), 127. 



Silver-spot butterfly (illus.), 126. 



Simple animals, characteristics of, 

 18. 



Single-celled animals, 11. 



Sinus, blood, 78. 



Siren (illus.), 178. 



Slug (illus.), 80. . / 



Snail, common (illus.), 80; arma- 

 dillo (illus.), 82 ; naked (illus.), 82. 



Snakes, 186 ; distribution of, 193. 



Snipes, 216. 



Somateria dresseri (illus.), 214. 



Species, origin of, 91. 



Sperm-cell, 20. 



Sphenodon punctatus (illus.), 199. 



Spicule, of sponge (illus.), 26; of 

 coral, 42. 



Spiders, organization of, 135 ; hab- 

 its, 136. 



Spinnerets, 135. 



Spiny-rayed fishes, 166. 



Sponge, development of (illus.), 

 21; distribution, 22; shape and 

 structure, 23. 



Spontaneous generation, 54. 



Springtail, 117. 



Squalus acanthias (illus.), 159. 



Squash-bug, 122. 



Squid (illus.), 87. 



Squirrels, 233. 



Starfish (illus.), 140 ; regeneration, 

 145; structure, 146. 



Steganopodes, 212. 



Stickleback, 164. 



Structure and function, correla- 

 tion of, 6. 



Strongylocentrotus purpuratus (il- 

 lustration), 144. 



Struthio camelus (illus.), 210. 



Sturgeon (illus.), 161. 



Sunfish (illus.), 166. 



Symmetry, radial and bilateral, 44. 



Swan (illus.), 213. 



Swift, 222. 



Tcenia solium (illus.), 51. 



Tapeworm (illus.), 50; develop- 

 ment, 51 ; in relation to regen- 

 eration, 51. 



Tarantula (illus.), 137. 



Teeth, use of, 2. 



Teleostei, 160. 



Termites (illus.), 120. 



Tern, 211. 



Terrapene Carolina (illus.), 189. 



