INDEX 



763 



Skull of Ornithorhynchus, 579 



of pigeon, 402 



of rabbit, 433 



of reptiles, 577 



of sheep, 494 



of snake, 580 



of Sphenodon, 580 



of thylacine, 495 



of turtle, 577 



table of bones of, 587 

 Sleeping sickness, 66 

 Slipper animalcule, 46 

 Slits, gill-. See Gill-clefts 

 Slow-worm, 550, 556 

 Snail, 264 



kidney of, 268 



nervous s^^stem, 268 



nutrition of, 267 



reproductive system of, 269 



shell of, 266 



torsion of, 266 

 Snakes, 550, 583, 593 

 Social insects, 260 

 Soil, action of earthworms on, 157 

 Solar plexus, 464 

 Solenocytes, 121, 122, 305, 306 

 Soles of feet, 418 

 Somatopleure, 627, 653 

 Somites, 192, 564, 565, 624, 627, 634, 

 650, 671. See also Segmenta- 

 tion, metameric 

 Sorex minutus, 476 

 Soricidae, 476 

 Spatangus, 298 

 Special creation, 709 

 Specialisation, 17 

 Species, 25, 706 

 Specific name, 25, 707 

 Sperm, 5. See also Spermatozoon. 



rosettes, 175 



sacs, 334, 619 

 Spermatheca, 173, 238, 269 

 Spermathecal pores of earthworm, 



160, 175 

 Spermatic cord, 455 

 Spermatids, 694 

 Spermatocytes, 100, 694 

 Spermatogenesis of earthworm, 174 



of rat, 541 

 Spermatophore of snail, 270 

 Spermatozoon, 5, 694 



of Ascaris, 138 



of crayfish, 216 



of earthworm, 174 



of Hydra, 100 



of man, 5 



of Nematoda, 138 

 Sperm sac, 334, 619 



Sperm-mother-cells of earthworm, 



173 

 Sphenodon, 550, 579, 580, 601 



Sphincter, pyloric, of dogfish, 322 



of rabbit, 442 

 Sphincters, 530 

 Spicules, 83, 283 

 Spiders, 148, 222 

 Spinal cord, 532 



diagram of fibres entering and 



leaving, 533 

 of frog, 383 

 of man, 532 

 of rabbit, 458 



nerves, 308, 337, 384, 463 

 Spindles, cell-, 502, 688 

 Spindle-tree, 252 

 Spine. See Vertebrae 



haemal, of dogfish, 316 



neural, 422 



of scapula of rabbit, 434 

 Spines of starfish, 288 

 Spinnerets, 222 

 Spinules of liver fluke, 119 

 Spiracle, 312, 322, 325, 590 

 Spiral valve of conus arteriosus, 370 



of intestine, 322 

 Spireme, 698 

 Spirochaetes, 224, 253 

 Splanchnocoele, 627 

 Splanchnopleure, 627, 651 

 Splanchnotome, 627 

 Spleen, 526 



of dogfish, 324 



of frog, 368 



of pigeon, 408 



of rabbit, 441 

 Sponge, bath, diagram of structure 



of, 87 

 Sponge bodies, complex, 84 



simple, 81 

 Sponges, 82 



branched calcareous, 85 



canal systems of, 86, 87 



dermal layer, 83 



food of, 84 



gastral layer of, 83 



larvae of, 87 



osculum of, 82 



pores of, 82 



siliceous and horny, 86 



skeletogenous layer of, 83 

 Spore formation in Amoeba, 35 



in Monocystis, 44 

 Spores, 45 

 Sporoblast, 73 

 Sporocyst, 125 

 Sporont, 45, 73. 77 



