32 J. BRONTE GATENBY 



For if Schaxol's granules aro chromatin, usinfj the word in 

 the sense that they are made of the same sort of material as 

 the chromosomes, either they must have originated from the 

 latter — have been budded off from them — or there must be 

 two kinds of chromatin in the egg nucleus. 



I cannot see how the adoption of the first alternative will 

 allow one still to hold that the present-day chromosome theory 

 is likely to be true ; and the very behaviour of the nucleolus 

 in Apantoles shows that there is a body other than the 

 chromosomes which can produce a nucleus. 



By placing one's belief in the second of the two alternatives — 

 in some form of ' binuclearity hypothesis ', one could also make 

 many of Schaxel's observations fit in with the more theoretical 

 aspect of the question. 



While my mind is as open as it well could be in view of my 

 own observations, I do not at present feel that Schaxel has 

 attacked the problem in the l)est way, and I refrain from 

 definitely accepting any of his views till some other observer 

 carefully reinvestigates his claims and uses all the best and 

 latest cytological techniques. 



Perhaps it should be mentioned that the above remarks do 

 not commit me to the espousal of any ' binuclearity hypothesis ', 

 though I feel that there is some good evidence for such a postu- 

 lation. 



(/) Centrifuge Experiments in Annelid Develop- 

 ment and what they demonstrate. 



It has been shown in this paper that the major part of the 

 granules of the egg of Saccocirrus is derived from nucleolar 

 material extruded from the nucleus. If these nucleolar extru- 

 sions represent Schaxel's chromidia or the granules which 

 form the secondary nuclei in parasitic Hymenoptera, and if 

 they are of chromatinic nature, and not merely metaplasm 

 or yolk, one might expect them to play some special part 

 during embryonic development. They might even represent 

 organ-forming materials. 



But apparently this is not the case : Lillio (43) has given 



