INDEX 



127 



Mechanism of membrane formation, 

 42, 43 ; inheritance, 1. 



Medusa, 71. 



Membrane, Descemet's, 110; of egg, 

 28; formation in artificial partheno- 

 genesis, 41-4 ; by chloroform, 39 ; 

 by haemolytic agents, 44; by neutral 

 salts of K and Na, 44 (tab.) ; by 

 various spermatozoa, 96. 



Mencl, E., 110. 



Menidia, 97. 



Meridional division, 65, 76. See Seg- 

 mentation. 



Merogony, 33, 53, 89. 



Mesenchyme,inEchinoderms, 3 (fig.), 

 4, 5, 95 ; in half-embryos of Cynthia, 

 75. 



Mesoderm, 111 ; absence of, in Ilya- 

 nassa, 73 ; in Ascaris, 12 ; in Frog, 

 10, 111 ; in spirally-segmenting 

 eggs, 68. 



Metazoa, growth-rate, 18-20. 



Micromeres, in compressed egg of 

 Nereis, 77 ; in dispermic eggs, 89 ; 

 in Echinoderms, 4 ; in spiral cleav- 

 age, 50, 51 (fig.). 



'Micropyle, 2, 27, 81. 



Minot, C. S., 15, 20. 



Mitosis, 10, 12, 13, 91 ; multipolar, 

 38. 



Modiolaria, 96. 



Moenkhaus, W. J., 97. 



Mollusca, cell-lineage in, 68 ; hetero- 

 geneous hybridization, 96 ; isolated 

 blastomeres of, 67, 73. 



Monaster eggs, 53, 54. 



Monsters, double, 63 (fig.), 71 ; head- 

 less, from centrifuged eggs, 80. 



Morgan, T. H., 37, 62, 71. 



Mosaic-theory, 59, 60, 70. 



Murex, 96. 



Mus, fertilization in, 28. 



Mytilus, cross-fertilization, 95. 



Nassa, 96. 



Nemertines, cell-lineage, 68 ; develop- 

 mental capacities of cells of, 73; 

 effect of calcium-free sea-water on 

 eggs, 66 ; isolated blastomeres, 67, 

 72, 77. 



Nereis, artificial parthenogenesis, 40; 

 cleavage centrosome, 32 ; fertiliza- 

 tion, 27, 28 ; segmentation under 

 pressure, 66, 77 ; vitelline mem- 

 brane, 28, 44. 



Newman, H. H., 99. 



Newt, double monster, 63 (fig.) ; iso- 

 lated blastomeres, 71 ; regeneration 

 of lens of, 77. 



Notochord formation, in Frog, 10 ; 

 in half-embryo of Cynthia, 75 ; 

 inversions of, 111. 



Nuclear division, see Nucleus. 



Nucleins, synthesis of, 17, 19. 



Nucleo-plasma ratio, 52, 55, 69 ; in 

 adult tissues, 59 ; in Crepidula egg, 

 58 (tab.). 



Nucleus, 88 ; in artificial partheno- 

 genesis, 45 ; characters transmitted 

 by, 89, 98 ; in dispermy, 53, 86 ; 

 division of, 33, 52, 59 ; in Echino- 

 derms, 2 ; in fertilization, 29, 30, 

 31 (fig.) ; in inheritance, 33, 88, 94, 

 108 ; karyokinetic division of, 23, 

 89 ; position in Frog's egg, 7 ; in 

 Protozoa, 88 ; qualitative division 

 of, 59, 65, 70, 88 ; size and number 

 of chromosomes, 54, 91, 93 ; surface 

 area of, 54, 55 ; volume, decrease 

 during development, 56. 



Nervous system in Frog, 10; in- 

 verted, 111. 



Oil-drops, 47 ; radial system of, 52. 



Ontogeny, 112. 



Ophelia, 40. 



Optic cup and lens, 109. 



Organ-forming cytoplasmic mate- 

 rials, 69, 78, 107. 



Osmotic pressure cause of artificial 

 parthenogenesis, 38, 40. 



Oxidation of substances in the egg, 

 41. 



Oxygen, chemotactic effect on pig- 

 ment-cells, 109 ; necessity for, in 

 hypertonic solutions, 41. 



Parthenogenesis, artificial, 33, 37, 89 ; 

 alteration of symmetry in, 47 ; with 

 cross-fertilization, 103 ; cytolysis, 

 41; irregular segmentation, 66 (fig.) ; 

 Loeb's theories of, 41 ; membrane 

 formation in, 41 sqq. ; number of 

 chromosomes in, 53 ; various 

 methods of inducing, 38, 40. 



Patella, isolated blastomeres, 67, 73. 



Pecten, 96. 



Percentage increments, 15-20. 



Perivitelline fluid, 27, 42, 79 ; space, 

 28. 



Petromyzon, artificial partheno- 

 genesis, 40. 



Pfliiger, E., 51, 79. 



Phallusia, 74. 



Phycomyces, growth -rate of hyphae, 

 18. 



Physa, centrifuged eggs of, 83. 



Pigment, in Arbacia, 81 ; in Ascaris, 

 84 ; in centrifuged eggs, 80, 81, 82, 



