494 



GENERAL ZOOLOGY 



Septum bulbi, 125 



Septum interaorticum, 126 



Septum principale, 126 



Serous membrane, 31, 94 



Serpentes, 451 



Serum, 134 



Serum albumin, 134 



Serum globulin, 134 



Serum tests, 299 



Sex chromosomes, 231, 232 



Sex determination, 233-235 



Sex inheritance, 275 



Sex-linked inheritance, 276-280 



Shallow-water animals, 362 



Sharks, 447 



embryos, 162 

 Sheep tick, 431 

 Sigmoid flexure, 102 

 Signals, 338 

 Sinanthropus pekinensis, 305, 307 



SlPHONAPTERA, 431 



Siren, 450 

 Sirenia, 456 

 Size, 11 

 Skeleton, action, 84 



appendicular, 55 



axial, 54, 55 



cat, 62 



fowl, 72 



frog, 66 



gorilla, 310 



human, 310 

 Skin, frog, 27 



human, 45, 46 



secretion of, by toad, 331 

 Skull, frog, 56-58 



human, 58, 310 

 Slime tube, 158 



Sloth, two-toed, symbiosis of, 347 

 Slugs, 434 

 Small intestine, absorption, 115 



blood vessels of, 116 



digestion in, 113, 114 



frog, 32, 100 



mucosa of, 101 

 Smell receptors, 189 

 Smith, E. A., 267 



Snails, 434 

 Snakes, 451 



adaptations, 338 



tongue of, 93 

 Somatic mitosis, 220 

 Somatotropic hormone, 206 

 Somite, 250 

 Sound receptor, invertebrate, 198 



vertebrate, 199 

 Species, 23, 290 

 Spermatocyte, 228 

 Spermatogenesis, 228 

 Spermatogonia, 228 

 Spermatozoa, 239 

 Sphenethmoid, 57 

 Sphenodon, 451 

 Spider crab, 347 

 Spinal accessory nerve, 179 

 Spinal cord, 175, 181 

 Spinal ganglia, 251 

 Spinal nerves, 180 

 Spindle cell, 136 

 Spiracle, 255, 426 

 Spiral valve, intestine, 101 

 Spireme, 221 

 Spleen, frog, 32, 33 



rat, 142 

 Sponges, 386, 388 

 Spongilla, 388 

 Sporozoa, 375 

 Springtails, 428 

 Squamosal, 57 

 Squamous epithelium, 42 

 Stagomantis, 429 

 Stapes, 202 

 Starfish, 240, 436, 437 



regeneration, 349, 350 

 Statocysts, 198, 435 

 Stearic acid, 114 

 Stenson's duct, 94 

 Stentor, 384 

 Sterna, 339 

 Sternalis muscles, 76 

 Sternohyoideus muscle, 76 

 Sternoradialis muscle, 76 

 ' Sternum, frog, 65, 67 



human, 65 



