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 .... 



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



spermatogenesis of Lepidosiren, from AGAR . 



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 ..... 



VI. Diagrams illustrating the hypotheses of telosyn- 

 desis and parasyndesis, after GREGOIRE 



VII. Maturation divisions with Tetrad formation in 

 Cyclops, from RUCKERT .... 



VIII. Development of the oocyte in Paludina, after 



POPOFF ....... 



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

 from KOSTANECKI and WIERZEJSKI 



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 ....... 



XI. Mitochondria in spermatogenesis of Lepidoptera, 

 from GATENBY ...... 



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

 from WILSON and LEAMING .... 



XIII. Oogenesis and spermatogenesis in Aphids, after 



MORGAN ....... 



XIV. Spermatogenesis of the Hornet, after MEVES | . 



XV. Spermatogenesis of the Hive Bee, from MARK and 



COPELAND . . . to follow plate XIV 



