LIST OF PLATES AND TEXT-FIGURES 



PLATES 



PLATE To face 



I. Echinus larvae from nucleated and non -nucleated 

 egg-fragments, after BOVERI. Amitotic nu- 

 clear division, from MARSHALL . . p. 15 



II. Stages of mitotic division in Sea-urchin egg, from 



WILSON and LEAMING . . . . p. 30 



III. Origin of centrosomes and spindle in the egg of the 



Axolotl, after JENKINSON . . . p. 46 



IV. Stages of the maturation divisions (meiosis) in the 



spermatogenesis of Lepidosiren, from AGAR . p. 63 



V. Prophases of the heterotype division in spermato- 

 cytes of the Guinea-pig, after MOORE and 

 WALKER. 

 Heterotype mitoses in spermatocytes of Steno- 



bothrus, after DAVIS p. 67 



VI. Diagrams illustrating the hypotheses of telosyn- 



desis and parasyndesis, after GREGOIRE . p. 69 



VII. Maturation divisions with Tetrad formation in 



Cyclops, from RUCKERT . . . p. 72 



VIII. Development of the oocyte in Paludina, after 



POPOFF . . . . . . p. 76 



IX. Production of polar bodies in the egg of Physa, 



from KOSTANECKI and WIERZEJSKI . . p. 78 



X. Conversion of the spermatid into the spermatozoon 



in Euschistus, after MONTGOMERY. 

 Sertoli cells in testicular tubule of the Rat, from 



KORSCHELT and HEIDER. 

 Apyrene spermatozoon of Vermetus, after KUSCHA- 



KEWITSCH p. 94 



XI. Mitochondria in spermatogenesis of Lepidoptera, 



from GATENBY .... . p. 96 



XII. Stages of fertilisation of the egg of the Sea-urchin, 



from WILSON and LEAMING . . . . p. 112 



XIII. Oogenesis and spermatogenesis in Aphids, after 



MORGAN p. 127 



XIV. Spermatogenesis of the Hornet, after MEVES . p. 134 



XV. Spermatogenesis of the Hive Bee, from MARK and 



COPELAND . .to follow plate XIV 



