INDEX 



125 



52 sqq., 69 ; internal factors of, 

 70 sqq. ; of nephridia, 68 ; with- 

 out cleavage, 69. 



Diminution of chromosomes in 

 Ascaris, 11, 12, 13 (fig.), 74 ; in 

 dispermy, 87. 



Diplokaryotic, 53. 



Dispermy, 53 ; in Ascaris, 86 sqq. ; 

 development of embryos, 91 ; in 

 Strongylocentrotus, 89 sqq. 



Division, cell-, 2, 11, 52 ; of centro- 

 some, 32 ; of chromosomes, 33 ; 

 equatorial, 4, 8, 11 ; karyokinetic, 

 23 ; latitudinal, 4, 8, 11 ; meri- 

 dional, 4, 8, 11 ; maturation, 23 ; 

 nuclear, 2, 11, 52 ; power of, re- 

 stored by fertilization, 33 ; simul- 

 taneous in parthenogenetic eggs, 

 38 ; see Segmentation. 



Dominant characters, 106. 



Doncaster, L., 102. 



Driesch, H., 66, 68, 73, 77. 



Drops of fluid, coherence of, to form 

 system, 49 ; of oil, radial system 

 of, 52. 



Earthworm, nephridia of, 68 ; re- 

 generation in, 112. 



Echinocardium cordatum, 105. 



Echinoderms, archenteron, 5; arms 

 of pluteus, 5, 100, 101, 109; arti- 

 ficial parthenogenesis in, 37,40; arti- 

 ficial parthenogenesis with cross- 

 fertilization, 103 ; blastula, 4, 72 ; 

 centrifuged eggs of, 81, 85 sqq. ; 

 cleavage altered by pressure, &c., 

 66 ; cross-fertilization, 94; develop- 

 ment of egg-fragments, 73, 77 ; 

 development in salt solutions, 

 109 ; dispermy in, 89 ; fertilization 

 membranes of, 27, 42 ; hybridiza- 

 tion, 95 sqq. ; isolated blastomeres 

 of, 67 ; membrane formation in, 

 45, 96 ; normal development of, 

 3 (fig.) ; number of chromosomes 

 in eggs, 54 ; plasma, nuclear ratio 

 in, 55 ; pluteus larva, 6 (fig.), 100 

 (fig.), 102 (fig.) ; separation of blas- 

 tomeres of, 49 ; symmetry of, 72 ; 

 various shaped chromosomes in, 

 94. 



Echinoids, see Echinoderms. 



Echinus acutus, 105. 



esculentus, 105, 106. 



microtuberculatus, 6 (fig.), 101. 



miliaris, 105. 



Ectoderm, Ascaris, 12 ; corneal, 110 ; 

 in dispermic eggs, 85, 86 ; in Echi- 

 noderms, 77 ; in Hydromedusae 



76 ; lens-forming, 110 ; of ventral 

 plate, 68. 



Egg, fertilization of, 30, 31 (fig.), 32 ; 

 maturation of, 24, 26 (fig.) ; strati- 

 fication of, 78. 



Egg-axis, 49, 91 ; in Ascaris, 11 ; in 

 centrifuged eggs, 80, 83 ; in di- 

 spermic eggs, 86 ; in Echinoderms, 

 2 ; in Frog, 7, 9, 64. 



Egg-fragments, enucleate, see Mero- 

 gony ; isolated, 70 ; segmentation 

 of, see Segmentation ; totipotence 

 of, 72, 76. 



Egg-structure, centrolecithal, 27 ; of 

 Cynthia, 34, 35 (fig.) ; of Frog, 6 ; 

 of Hydromedusae, 70 ; of Strongy- 

 locentrotus, 2 ; telolecithal, 6, 11, 



27, 51, 71 ; of vertebrates, 27. 

 Embryology, comparative, 1 ; experi- 

 mental, 2. 



Embryonic symmetry, see Symmetry. 



Endoderm, in Ascaris, 12 ; in 

 Echinoderms, 77 ; -forming sub- 

 stance, 78 ; in Hydromedusae, 76. 



Entrance funnel, 28, 30 ; position of 

 grey crescent determined by, 64, 65. 



Epaulettes, in pluteus, 6 ; in hybrid 

 larvae, 105. 



Equator of egg, 2, 7. 



Equatorial cleavage, see Segmenta- 

 tion. 



Erdmann, R., 55. 



Errera, L., 18. 



Ferments, extra-cellular, 20. 

 Fertilization, 27, 33, 46 ; of Axolotl, 



28, 30 (fig.), 31 (fig.), 32 ; of centri- 

 fuged eggs, 84 ; cross-, 42, 94 sqq. ; 

 spindle, 31(fig.); and symmetry, 64. 



Fertilization membrane, 27 ; arti- 

 ficial formation of, 39. 



Fischer, M. A., 40. 



Fishes, heterogeneous hybridization, 

 97. 



Frequencies, of angle between first 

 furrow and sagittal plane, 61 

 (tab.) ; of angle between symmetry 

 plane of egg and embryo, 48 (tab.). 



Frog, artificial parthenogenesis, 40 ; 

 blastopore formation in, 9 (fig.) ; 

 centrifuged eggs of, 79, 85 ; cleav- 

 age, 8, 49 ; development of, 6 ; 

 double monster, 71 ; first furrow 

 and sagittal plane, 61, 65 ; grey 

 crescent in egg of, 7, 8 (fig.), 64, 

 65 ; half-embryos, 60 (fig.) ; inver- 

 sion of eggs, 71, 78; inversion 

 of embryonic organs, 111; optic 

 vesicle of, 110 ; position of axis in 

 eggs of, 28 ; effect of pressure on 



