128 



INDEX 



84 ; in Cumingia, 82 ; in Cynthia, 

 34, 35 (fig.) ; in Echinus miliaris, 

 105; in entrance-funnel, 29; in 

 Frog, 6, 80 ; in Strongylocentrotus, 

 2, 82 ; transmission of, 97. 



Pilidium, 66. 



Planorbis, centrifuged eggs of, 83. 



Plateau, J., 52. 



Pluteus larva, abnormal skeletons of, 

 100, 109 ; arms of, 5, 100 sqq. ; from 

 - and i-blastomeres, 67 ; of Echi- 

 nus microtuberculatus, 6 (fig.) ; of 

 hybrids, 101, 102, 105, 107; of 

 Sphaerechinus granularis, 100 



(fig.). 

 Polar bodies, 2, 25, 26 (fig.) ; eggs, 



78; furrows, 50; lobe, 67 (fig.), 



73, 74. 

 Polarity, alteration of, 71, 78 ; of 



centrifuged eggs, 81, 85; of ovum, 



in Sea-urchin, 2. 

 Polychaeta, Amphitrite, 46 ; in 



hybridization, 96 ; Nereis, 27. 

 Polynoe, 40. 

 Popoff, M., 19. 

 Potassium chloride, 38, 69 ; cyanide, 



39, 41. 

 Potentiality of animal and vegetative 



blastomeres, 71, 72, 73 ; of isolated 



cells, 74 ; limitation of, 77. 

 Pressler, K., 111. 

 Pressure, effect of, on segmentation, 



65, 66 ; osmotic, 38, 40. 

 Protoplasmic or animal pole, 7. 

 Protozoa, rate of cell-division, 18, 20 ; 



role of nucleus in, 88. 

 Pulmonates, eggs centrifuged, 83, 85. 

 Punctured eggs, artificial partheno- 

 genesis, 40 ; grey crescent formed 



in, 47. 



Quadripartite ova, 91 ; development 



of, 92. 

 Qualitative division of nucleus, 59, 



88. 

 Quarter blastomeres, 66, 67, 71, 76, 



77. 

 Quetelet, A., 16. 



Radial cleavage, see Segmentation. 



Radial symmetry, see Symmetry. 



Rana, 110. See Frog. 



Rate of growth, 15, 16 ; maximum in 

 man, 16 (tab.), 17 ; of cleavage, 

 99. 



Ratio, cell to chromosome number, 

 54, 56, 57 ; cell, nuclear and chro- 

 mosome volumes, 56 (tab.) ; cell- 

 volume to surface area of nucleus, 

 55 ; nuclear size .to chromosome 



number, 54 ; nuclear surface to 

 chromosome volume, 57 ; nucleo- 

 plasma, 52, 55, 58, 59, 69. 



Recessive c/haracters, 106. 



Redistribution of materials in cyto- 

 plasm, 76, 83. 



Regeneration, 77, 112. 



Roberts, C., 21. 



Robertson, T. B., 17, 47. 



Roux, W., 52, 59, 60, 89. 



Sagittal plane of Frog's egg, 61 (tab.) ; 

 and first furrow, 65. 



Salamander, development of sper- 

 matozoon, 24, 25 (fig.). 



Salts, artificial parthenogenesis, 38 

 sqq. ; effect on segmentation, 66, 

 69 ; in heterogeneous hybridiza- 

 tion, 94 ; in membrane formation, 

 41, 44 ; skeleton of pluteus, 109. 



Samassa, P., 71. 



Saponin, 24. 



Schulze, 0., 62. 



Scott, J. W., 40, 46. 



Sea-urchin, see Echinoderms. 



Sea-water, absorption by egg, 44 ; 

 artificial, 49; effects of diluting, 

 66 ; hyper-alkaline, in hybridiza- 

 tion, 95. 



Secretion of substances in growth, 

 14. 



Seeliger, 0., 100. 



Segmentation, 37 sqq., 52 ; alterna- 

 tion of directions of, 50 ; in artifi- 

 cial parthenogenesis, 38, 40, 45, 

 46 ; in Ascaris, 11, 13 (fig.), 76, 

 84, 86 ; bilateral type of, 49, 50 ; 

 causes of end of, 52, 55 ; cavity, 4, 

 8, 10, 14, 52 ; of centrifuged eggs, 

 74, 79, 80, 83 ; in Dentalium, 67 

 (fig.) ; of dispermic eggs, 86, 87, 

 91 ; in Echinoderms, 2, 3 (fig.) ; 

 of egg- fragments, 76 ; in Frog, 8, 

 49 ; of hybrids, 95 ; irregular, 66, 

 88 ; iso-bilateral type of, 40 ; of 

 isolated blastomeres, 66, 67, 73, 

 76 ; at low temperatures, 68 ; nu- 

 cleo-plasma ratio during, 58 ; par- 

 tial, 68 ; patterns of, 37, 48, 49, 66, 

 69 ; under pressure, 66, 72, 76 ; 

 radial type of, 23, 49 ; rate of, 99 ; 

 of Sepia, 50 (fig.) ; sequence of, 8 ; 

 spiral type of, 49, 50, 51 (fig.), 68 ; 

 suppression of, 69. 



Sense organ, see Apical organ. 



Sepia officinalis, 50 (fig.). 



Sequence of divisions in Frog's egg, 8. 



Shaking, effects of, 53, 66, 90. 



Shearer, C., 105. 



Skeleton of pluteus, 5, 6 (fig.) ; of 



