INDEX 



129 



hybrids, 105 sqq. ; from tripartite 

 ova, 92. 



Soap-bubbles, 52. 



Solutions, hypertonic and isotonic, 

 38 ; of varying osmotic pressures, 

 38 (tab.). 



Somatic cells of Ascaris, 12, 13 (fig.), 

 86. 



Specific characters, 98, 99. 



Spemann, H., 109, 110, 111. 



Spermatozoon, 23, 89 ; acrosome, 24, 

 27, 89 ; axial filament of, 24 ; deve- 

 lopment of, 24, 25 (fig.) ; entrance 

 of, 28, 29; relation to first fur- 

 row, 64 (fig.) ; sperm-aster, 29, 32 ; 

 sperm-path, 29. See Centrosome. 



Sphaerechinus granularis, 100 ; cross- 

 fertilization with, 95 ; hybrid plu- 

 teus, 102 (fig.) ; normal pluteus, 

 100 (fig.). 



Spicules, 4, 5, 109. 



Spina bifida, centrifuged eggs, 78. 



Spindle of Axolotl, 30, 31 (figs.), 32 ; 

 bi-polar, necessary for normal seg- 

 mentation, 46 ; in centrifuged eggs, 

 84, 85 ; double and quadruple in di- 

 spermic eggs, 89, 90 (fig.). 



Spindle-fibres, function of, 47. 



Spiral type of cleavage, 51 (fig.)- See 

 Segmentation. 



Spooner, G. B., 83. 



Standard deviation, 21. 



Starfish, 42, 94. 



Steinbriick, H., 101. 



Stenotomus, 97. 



Stevens, N. M., 74. 



Stimuli, in artificial parthenogenesis, 

 37 ; exerted by organs in develop- 

 ment, 109 ; in regeneration, 112. 



Stockard, C., 110. 



Stomodaeum, in Ascaris, 12 ; in 

 Echinoderms, 5 ; in Frog, 11 ; de- 

 veloped from isolated blastomeres, 

 73, 77. 



Stratification, 78 ; axis of, 81, 83. 



Streeter, G. L., 111. 



Strongylocentrotus, abnormal deve- 

 lopment of, 96, 98 ; artificial par- 

 thenogenesis, 37, 40, 45 ; cross- 

 fertilization, 94, 95, 103 ; dispermic 

 eggs of, 90 (fig.) ; Franciscanus, 

 106 ; lividus, normal development 

 of, 2, 3 (fig.) ; purpuratus, 45, 106. 

 See Echinoderms. 



Surface-tension, 47, 49 ; in membrane 

 formation, 43. 



Sutton, W. S., 94. 



Symmetry, alteration of, by centri- 

 fuging, 34, 47, 79, 83, 85 ; altera- 

 tion of, at fertilization, 34, 47, 72, 



76 ; in artificial parthenogenesis, 

 47, 48; of Ascaris egg, 11; bilateral, 

 7, 48, 64, 72 ; of egg and embryo, 

 7, 48, 63 ; of embryo, 48, 63, 64, 

 69 ; of Frog's egg, 7, 69 ; plane and 

 first furrow, 61, 62 ; plane and sa- 

 gittal plane, 61, 62 ; radial, 7, 64, 

 76. 



Tadpole, 11 ; optic vesicle, 109 ; pres- 

 sure experiments, 66. 

 Teichmann, E., 90. 

 Teleostean egg, 50. 

 Telolecithal, see Egg-structure. 

 Temperature, 56, 68 ; affecting hybrid 

 larvae, 102 ; coefficient, 43 ; quo- 

 tient, 43 (tab.). 

 Tennent, D. H., 94, 106. 

 Tetrahedron of cells, 86. 

 Tetrasters, 89. 

 Thalassema, 40, 46. 

 Thelykaryosis, 53, 54, 104. 

 Theory, of Loeb, artificial partheno- 

 genesis, 41 ; of Eobertson, syn- 

 thesis of nucleus, 17, 19 ; of Roux, 

 mosaic-theory, 59, 60, 61 ; of Weis- 

 mann, 59. 



Totipotence, see Egg-fragments. 

 Toxopneustes, 106. 

 Transmission of characters, 94, 96, 



98, 99 ; by nuclei, 33. 

 Transplantation, of auditory vesicle, 

 110 ; of limb-bud, 112 ; of optic 

 vesicle, 110. 

 Trembley, Abbe, 77. 

 Tripartite embryos, 92 ; ova, 91. 

 Trochophore, 66, 83. 

 Trochus, 96. 



Trout larvae, correlation coefficients, 

 22 (tab.) ; growth and variability, 

 21. 

 Turbellarians, 68. 



Urea, artificial parthenogenesis, 38. 

 Urodela, regeneration in, 112. 



Variability, coefficient of, 21 ; and 

 growth-rate, 21. 



Vegetative pole, 2, 7. 



Venus, 96. 



Vernon, H. M., 102. 



Vertebrates, artificial partheno- 

 genesis, 40 ; egg-structure, 27 ; in- 

 teraction of parts in, 109 sqq. 



Viscera, inverted, 111. 



Warburg, 0., 41. 



