320 



INDEX. 



INIaternal sacrifice, 256, 257 



Ivlaupas on conjugation and multi- 

 plication of infusorians, 149, 150, 

 228, 229, 235, 236 ; on uses of 

 fertilisation, 163-166; on theory 

 of organic immortality, 260 



Mayflies, 257, 258 



Meehan, investigations on sex of 

 plants, 47, 49 ; on cross-fertilisa- 

 tion, 75 



Menstruation, 244, 245 



Mesozoa, liberation of germs in, 60, 



255 

 Metabolism, see Protoplasm 

 Micropyle, 103 

 Microstomum, 195, 225 

 Miescher on the milt of salmon, 



115 



Migration of sex-cells, 60 



Milk, 250 



Minot on polar globules, 106 ; 



theory of genoblasts, 118, 132; on 



parthenogenesis, 180, 181 

 Mivart on sexual selection, 13, 14 

 jNIolluscs, hermaphroditism among, 



72 

 Molothrus, 278 

 INIoonwort, 226, 227 

 Moss, alternation of generations, 



201, 205, 206 

 Myzostomata, hermaphroditism of, 



11 



Natural selection, a check on diver- 

 gence of sexes, 30 ; scope of, 303, 

 307, 311, 313, 314 



Nematodes, alternation of sexual 



generations in, 208 

 Neo-Malthusianism, 292-298. 

 Notodelphys, 253 

 Nototrema, 253 

 Nucleus, behaviour in fertilisation, 



145 ; essential elements of, 240 

 Nussbaum, 94, 160 

 Nutrition, influence on sex, 41 

 Nutrition versus reproduction, 



223-225 

 Nutrition of young, 248, 249 



Obstetric frog, 253, 254 

 Organs of reproduction, 57-64 

 Orthonectids, bursting of female, 257 



Oviparous animals, 248 



Oviparous mammals, 24S 



Ovipositors, 62 



Ovists, 83, 84, 157 



Ovo-viviparous animals, 248 



Ovulation, 242, 243 



Ovum, 97-108; envelopes of, 103; 

 maturation of, 104-107 ; libera- 

 tion of, 242, 243 



Ovum theory, 82 



Owen on somatic and reproductive 

 cells, 93 ; on residual spermatic 

 force, 212 



Pedogenesis or juvenile partheno- 

 genesis, 173 



Pairing, early forms of, 265 



Paper nautilus, brood-shell of 

 female, 254, 255 



Paramecium, conjugation of, 149 



Parental care, 270-274, 312 



Parental sacrifice, 255, 256 



Parthenogenesis, 169-187 



Parturition, 247, 248 



Penis, 61, 247 



Pfliiger on polyspermy, 34 ; on sex 

 in tadpoles, 41 



Pigments, expressions of disruptive 

 processes, 24 



Pigeon's milk, 250 



Placenta, 248 



Planarians, multiplication of, 229 



Plants, determination of sex in, 47 

 48 ; origin of sex among, 127 ; 

 conjugation in, 143 ; fertilisation 

 in, 140, 159; parthenogenesis in, 

 175, 176; asexual reproduction 

 of, 191, 192 



Plasmodium, 150, 151 



Platner on sex-cells in snail, 125 



Ploss on embryonic hermaphrodi- 

 tism, 33, 66 



Polar globules, 105, 106, 179-185 



Pollen-grain, 229, 230 



Polyspermy, 34 



Polystomum, 243 



Population question, 289-298 



Precocious reproduction, 207, 243, 

 244 



Preformation, theory of, 83, 84 



Primary sexual characters, 3 



Protococcus, 127 



