INDEX. 



719 



Solitaire, 547 



Somateria moUissima, 543 



Somite, 266 



Sorex platyrhinus, 587 



Sounds produced by insects, 349 



Sounds, fishes', 442 



Spalax, 586 



Sparrow, 555 



Spatangus, 134 



Specialization, 6 



Species, origin of, 672 



variation of, 10, 673, 673 

 Spermaceti, 593 



Spermatozoa, formation of, 644 

 Spliaerodonim, 231 

 Sphargis coriacea, 510 

 Splienodon, 511 

 Spheotyto cunicularia, 549 

 Sphex ichneumonea, 363 

 Sphinx, 359 

 Spiders, 343 

 Spirialis Gouldii, 239 

 Spirula Peronii, 361 

 Sphyrna zygsena, 431 

 Spirorbis, 237 

 Sponges, 42 



silicious, 47 



useful, 49 

 Spongia adriatica, 49 



equina, 49 



gossypina, 49 



tubulifera, 49 

 SpoDgilla, 47 

 Spoonbill fish, 428 

 Sporocyst of Nematodes, 151 

 Spring-tails, 344 

 Squalus Americanus, 430 

 Squamella oblonga, 176 

 Squid, anatomy of, 373 

 Squilla, 392 

 Squirrels, flying, 583 

 Star-flsh, 96, 109, 111 



anatomy of, 96 

 Star worm, 331 



Statoblast, 187 

 Stegocephala, 483, 488 

 Steller's manatee, 596 

 Stentor polymorphus, 36 

 Sternum of insects, 309 

 Stick insect, 677 

 Stickleback, 456 

 Stilt, 546 

 Sting rays, 424 

 Stomapoda, 393, 305 

 Stbne lilies, 101 

 Strobila of Hydrozoa, 66 

 Strobila of Planarians, 144 



tape-worms, 156 

 Strobilation in worms, 144, 145 

 Struggle for existence, 673 

 Struthio camelus, 539 

 Sturgeon, embryology of, 427 

 Sturgeon, 437 

 Stygicola dentata, 459 

 Stylaster, 58 

 Styliola vitrea, 338 

 Styloohus elliptica, 143 

 Stylocordyla, 48 

 Stylops, 353, 354 

 Sucker, 453, 454 

 Suctoria, 40 

 Sun-fish, fresh water, 455 



banded, 455 



spotted, 456 



salt-water, 463 

 Swimming, in fishes, 444 

 Sycandra, 44 

 Sycon ciliatum, 45 

 Syllis, 335 



Symmetry, bilateral, in cteno- 

 phores, 93, 93 



echinoderms, 130 

 Symphyla, 344 

 Synapta, 134, 135 

 Syncarida, 373 

 Syngnathus peckianus, 461 

 Synthetic types, 483, 679 

 Syrinx, 526, 552 



