2 J. BRONTE GATENBY 



PAGE 



9. Cells found in the Male, intermediate between Spermato- 

 cyte AND Oocyte ........ 20 



10. Discussion ........ 



(a) General ........ 



(h) The Preciseness of Modern Technique for the Cytoplasmic 



Inclusions and for Chromatin .... 



(r.) On the Supposed Chromatinic Nature of Extruded Nucleo 



lar Material ....... 



((/) On the Special Part played by the Nucleus during 



Oogenesis ........ 



{(') SchaxeFs Chromatin Emission .... 



(/') Centrifuge Expeiiments in Annelid Development and 



what they demonstrate ..... 



(f/) The Probable Part played by the Mitochondria and Golgi 



Apparatus in Heredity ..... 



11. Summary . . . . 



12. Bibliography ........ 



13. Explanation of Plates ...... 



21 

 21 



22 



24 



29 

 30 



32 



33 

 37 

 42 

 4^^ 



1. Introduction. 



In this papor I have attempted to shed further Hght on that 

 difficult problem, the oogenesis of an Annelid : while Sacco- 

 cirrus, as Goodrich has shown (26), is an Archi-annelid closely- 

 related to Protodrilus, it is probably much like other Annelida 

 so far as its oogenesis is concerned. 



I was influenced to undertake a study of the oogenesis of 

 an Annelid by three special reasons, namely, Schaxel has 

 described ' chromatin ' emission in A r i c i a f o e t i d a , a 

 Polychaete ; Hempelmann and Buchner have both described 

 most peculiar peri-nuclear extruded bodies at one period of 

 oogenesis of Saccocirrus ; and, finally, Saccocirrus is an 

 example of precocious entry of the sperm into the young 

 oocyte : we know that the head of the sperm hes quiescent 

 till the oocyte is ripe, and I believe that this would offer the 

 opportunity of observing whether the tail of the sperm entered 

 the oocyte, and (if so) whether it took any special part in 

 fertilization. 



