224 



CYTOLOGY 



Sex chromosomes in Aphis, 116 



in Ascaris nigrovenosus, 114 



in Birds, in 



in Echinoderms, in 



in hermaphroditism, 113 



in Insects, 99, 101, 103, 104, 105, 106, 107 



in Lepidoptera, 112 



in Mammals, no 



in Nematoda, 109 



in parthenogenesis, 115 



in Phylloxera, 118 



in syndesis, 106 



outside the meiotic phase, 106 



relation to determination of sex, 121 

 Sex, determination of, 121 

 Sex-limited inheritance, 179 

 Sex-linked inheritance, 179 

 Soma, differentiated from gonad, 81 

 Spermatid, 30 

 Spermatocyte, 29 

 Spermatogonium, 29 

 Spermatozoon, 67, 70 



development of, 68, 70 

 Spindle, 21 

 Spireme, 9 

 Sporophyte, 212 

 Strepsitene stage, 34 

 Synapsis, 38 



| Syncytium, 3 

 Syndesis (see also Parasyndesis), 33, 48 



function of, 175 

 Synergidae, 213 

 Syngamy, 72, 74, 75 

 Synizesis, 39, 54 



Telophase, n, 14 

 Telosynapsis, 43 

 Telosyndesis, 43, 45 

 Tetrad, 49 

 Tetraploid nuclei, 148 



plant, genetics of, 170 

 Tetraster, 163 

 Triaster, 164 

 Triploid nuclei, 150, 213 

 Trophochromatin, 155, 193 

 Trophonucleus, 202 



Univalent chromosomes, 34 

 X chromosome, 101 



Y chromosome, 101 



Yolk, 63 



Yolk nucleus, 64, 200 



Zygotene stage, 33 



THE END 



Printed by R. & R. CLARK, LIMITED, Edinburgh. 



