INDEX. 



697 



Silverfish, 477 

 Simia, 651 

 Simiid^e, 651 

 Simuliidse, 493 

 Sinupalliata, 368 

 Sinus frontalis. 539 

 Sinus, splienoid, 539 

 Siphon, 345, 387, 360 

 Siplionaptera, 493 

 Siplionophora, 240. 243 

 Siphonophores, 1G6 

 Siphonostomate, 371 

 Siphonostomata, 422 

 Sipliuncle, 388 

 Sipunculoida, 317 

 Sipunculus, 317 

 Siredon, 36 

 Siren, 586 

 Sirenia, 644 

 Sirex, 485 

 Siricidte, 4S6 

 Sixth sense, 125, 53S 

 Slialis, 571 

 Skin, 76 

 Skull, 519 



Skull of mammals, 619 

 Skunk, 647 

 Skylark, 616 

 Slime animals, 198 

 Slime eels, 557 

 Slime moulds, 198 

 Sloths, 636 

 Smell, organs of, 126 

 Smelt, 576 

 Snakes, 600 

 Snapping turtle, 596 

 Snout beetles, 485 

 Snow flea, 477 

 Social animals, 167 

 Soft-shell crab, 437 

 Soft-shelled turtle, 596 

 Solasteridte, 337 

 Sole, 578 

 SolemyidK, 367 

 Solen, 368 

 Solenoconcha;, 36c, 

 Solenogastres, 35S 

 Solenoglypha, 601 



Solenoglyphic tooth, 600 



Solenids, 368 



Solidungula, 641 



Solifug:e, 449 



Solpuga, 450 



Solpugida, 449 



Somatic cells, 143 



Somatic layer, 159 



Somatopleure, 159 



Somites, 305 



Song birds, S16 



Sorex, 637 



Soricidce, 637 



Sowbug, 442 



Spadella, 298 



Spadix, 238 



Spanish flies, 484 



Span worms, 494 



Spatarigoidea, 346 



Species, 10 



Species, nature of, 19, 25 



Species, physiological characters of, 27 



Spelerpes, 587 



Speotyto, 617 



Spermaceti, 646 



Spermatophore, 392 



Spermatozoa, 8i 



Spermatozoids, 202 



Sperm nucleus, 149 



Sperm whale, 646 



Sph^ridia, 330 



Sphserogastrida, 451 



SphKroma, 442 



Sphteromidie, 442 



Spha;rophr\'a, 212 



SphierozoidiC, 195 



Sphargis, 595 



Sphenethmoid bone, 581 



.Sphcnodon, 596 



Sphenoidalia, 521 



Sphenoid bone, 523, 620 



Sphenoid sinus, 539, 624 



vSphenopalatine ganglion, 537 



.Sphenotic bone, 522 



Spherical animals, 135 



Sphingina, 495 



Sphyranura, 274 



Spicula, 300 



