INDEX 



defined, 27-28, 265, 267 



degree of difference between, 265 



in asexual animals, 266 



origin from Rassenkreise, 227 



origin of, 86 



overlapping, 30, 31 



problem summarized, 269 



sympatric, 271 



synthesis, 301 

 Spencer, Herbert, 5, 79, 80 

 Spencer, W. P., 208 

 Sphenodon, 169, 170 



pineal eye of, 44-45 

 Sphenopsida, 113, 118-120 



origin of, 116 

 Spietli, H. T., 276 

 Spiral cleavage, 140 

 Spirochaetes, 100 

 Sponges, 133-134 



larva of, 133 



reproduction in, 133 

 Spontaneous generation, 90 

 Spoonbill, 161 

 Spores, of land plants, 116-117 



of moss, 112 

 Sporophyll, defined, 117 

 Sporophyte, 108 

 Sporozoa, 128 

 Squalus, vertebrae of, 33 

 Squamata, 171 

 Squid, 142 



Stadler, L. J., 208, 213 

 Stakman, E. C, 237 

 Stanley, W. M., 91, 110 

 Starfish, 4, 149 

 Stars, composition of, 93 

 Stebbins, G. L., 85, 212, 260, 299, 304, 



307 

 Stebbins, R. C, 267-269 

 Steinheim skull, 192 

 Sterility, hybrid, 279-282 



interspecific, 277-279 

 genetics of, 279 

 Sterilization by heat, 169 

 Stem, Curt, 206 

 Stirton, R. A., 75 

 Straus, W. L., Jr., 184 

 Strobih, defined, 1 17 

 Sturgeons, 161-163 

 Sturtevant, A. H., 220, 250 

 Subspeciation, and isolation, 270-271 

 Subspecies, as incipient species, 5, 212 



formation of, 212 



genotypes of, 212, 213 



geographic, 209-212 

 Suctoria, 131-132 

 Sugars, polymers of, 94 

 Sukatchew, W., 234 

 Sumner, F. B., 248 

 Sun, 93 



Sunflowers, 291 

 Swamping of variation, 270 

 Swanscombe skull, 192 

 Swanson, C. P., 229 

 Sweepstakes routes, 318-320 

 Swim bladder, 163 

 Swinnerton, C. F. M., 246 



Sycamore. See Platanus 

 Sijnamoeba, 134 

 Synapsis, specificity of, 214 

 Systemic mutation, 226, 329, 330 

 Systematics, new, 84 



Tachyeres, recapitulation in, 51 

 Tadpole larva, 149, 157, 158 

 Tail, of Primates, 43 

 Talpidae, 39 

 Tapeworms, 139 

 Tapir, 18 

 Taraxacum, 234 

 Tardigrada, 146 

 Tar pits, burial in, 68 

 Tarsiers, 18, 179, 180, 182 



fossil, 183 

 Taxonomic categories, 28 



diagrams, 29 



hierarchy, significance of, 29-31 



ladders, 29 



maps, 29 

 Taxonomy, 27-31 



modeled on permutations of genes, 

 264 

 Teedi, australopithecine, 187 



gorilla, 187 



in horse fossils, 73, 74 



labyrinthodont, 165, 166, 167 



origin of, 160 



priniate, 178, 184, 187, 189 



reduction of, 153 



vertebrate, 153 



wisdom, 43 

 Teleosts, 162, 163 

 Tenrec, 38, 39 

 Tertiary Period, 64 

 Tetrapod limbs, 41-42 

 Tetraptera, in Drosaphila, 265 

 Thallophyta, 100-102 

 Thallus, 112 

 Thecodontia, 171 

 Therapsida, 172 

 Thomas, H. H., 127 

 Thompson, D'Arcy, 261, 262 

 Thorium 232, 66 

 Thyroid, 55 

 Tiegs, O. W., 154 

 Timofeeff-Ressovsky, N. W., 234 

 Tippo, O., 127 

 Tit, mimicry in, 246 

 Tmesipterus, 114 

 Tornaria larva, 148, 157 

 Tracheophyta, 113-127 



origin of, 125 

 Trachylina, 136 



Tradescantia, autotetraploidy in, 297 

 Translocation, 218-219, 283-287 



and evolution, 221-222 



complexes, 285 

 Tree ferns, 121 

 Tree of hfe, 29-31 



form of, 151 

 Tree slirews, 178-179 

 Trematoda, 139 

 Triassic Period, 65 

 Trichocysts, 131 



851 



