306 KING. [Vou. XIX. 
they retain the characteristic structure shown in Figs. 39, 40, 
43, etc., and are therefore always to be distinguished from the 
oxychromatin threads. The chromosomes are never united 
with the nucleoli, although sometimes, as shown in Figs. 36, 
7 and 39, a nucleolus is in contact with a chromatin thread ; 
neither is there any connection between the basichromatin fila- 
ments and the oxychromatin threads. The latter stain much 
more intensely than the former and always appear to be com- 
posed of a series of rounded granules, they never have the 
feathery structure of the chromosomes. After the stage of 
Figs. 33-36, the chromosomes become widely distributed 
throughout the nucleus, and only a very few of them are 
found paired in later stages of development. 
In a preliminary paper on the oogenesis of Triton, Janssens 
(46) gives a brief account of the changes taking place in the 
young odcytes which seems to show that the behavior of the 
chromatin in the eggs of this amphibian is somewhat different 
from that I have found in Bufo. Janssens finds that synizesis 
occurs during the early growth period of the oocyte, but he 
states that the reduced number of chromatin filaments appears 
shortly after this stage and that these filaments subsequently 
split longitudinally, the sister threads always remaining to- 
gether in later development. 
Carnoy and Lebrun (15-18; Lebrun, 58, 59) have written 
an elaborate series of memoirs dealing with the germinal vesicle 
and the polar bodies in various species of Batrachians. They 
have not studied the primordial germ-cells or the early growth 
stages of the oocytes, and in every case their investigations be- 
gin with the young ovum at a stage about like that of my Fig. 
27. Although the details of the developmental processes in 
the ova differ somewhat in the various species, Carnoy and 
Lebrun invariably find that, in the earliest stage which they 
have studied, the nucleus contains a chromatin filament which 
seems to be continuous. Later this filament disintegrates and 
gives rise to “primitive nucleoli” which move to the centre of 
the nucleus and there resolve into chromatin threads of vari- 
ous types. These chromatin threads soon break up into minute 
