INDEX. 
Solitaire, 547 
Somateria mollissima, 543 
Somite, 266 
Sorex platyrhinus, 587 
Sounds produced by insects, 349 
Sounds, fishes’, 442 
Spalax, 586 
Sparrow, 555 
Spatangus, 206 
Specialization, 6 
Species, origin of, 672 
variation of, 10, 672, 673 
Spermaceti, 593 : 
Spermatozoa, formation of, 644 
Spherodorum, 231 
Sphargis coriacea, 510 
Sphenodon, 511 
Spheotyto cunicularia, 549 
Sphex ichneumonea, 363 
Sphinx, 359 
Spiders, 342 
Spirialis Gouldii, 289 
Spirula Peronii, 261 
Sphyrna zygena, 421 
Spirorbis, 175 
Sponges, 42 
Silicious, 47 
useful, 49 
Spongia adriatica, 49 
equina, 49 
gossypina, 49 
tubulifera, 49 
Spongilla, 47 
Spoonbill fish, 428 
Sporocyst of Nematodes, 109 
Spring-tails, 344 
Squalus Americanus, 420 
Squamella oblonga, 176 
Squid, anatomy of, 288 2457 
Squilla, 292 ; 
Squirrels, flying, 583 
Star-fish, 178, 191, 193 
anatomy of, 178 
Star-worm, 159 
719 
Statoblast, 145 
Stegocephala, 482, 488 
Steller’s manatee, 596 
Stentor polymorphus, 36 
Sternum of insects, 309 
Stick insect, 677 
Stickleback, 456 
Stilt, 546 
Sting rays, 424 
Stomapoda, 292, 305 
Stone lilies, 183 
Strobila of Hydrozoa, 66 
Strobila of Planarians, 102 
tape-worms, 114 
Strobilationinworms, 102,108,173 
Struggle for existence, 673 
Struthio camelus, 539 
Sturgeon, embryology of, 427 
Sturgeon, 427 
Stygicola dentata, 459 
Stylaster, 58 
Styliola vitrea, 238 
Stylochus elliptica, 101 
Stylocordyla, 48 
Stylops, 353, 354 
Sucker, 453, 454 
Suctoria, 40 
Sun-fish, fresh-water, 455 
banded, 455 
spotted, 456 
salt-water, 462 
Swimming, in fishes, 444 
Sycandra, 44 
Sycon ciliatum, 45 
Syllis, 215 
Symmetry, bilateral, in cteno- 
phores, 92, 93 
echinoderms, 202 
Symphyla, 344 
Synapta, 216, 217 
Syncarida, 272 
Syngnathus peckianus, 461 
Synthetic types, 488, 679 
Syrinx, 526, 552 
