No. 2] THE OOGENESIS OF BUFO LENTIGINOSUS. 309 
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oogenesis stand in direct contradiction to those cited above. 
Born (9, 10) states that in the egg of Triton the chromatin 
skein “sich aus dem Chromatingertist des Ureies direkt her- 
leitet.””. Although at one period of development the chromatin 
threads stain faintly and the chromatin substance can only 
rarely be distinguished from the granular karyoplasm, Born 
does not believe that the chromatin disappears or leaves the 
nucleus at this time, but that ‘“‘sich dasselbe nur ausserst fein in 
der umgebenden Kerngrundsubstanz vertheilt habe.” Later the 
chromatin threads are formed again, and they appear in 
pairs, lying parallel or closely intertwined as in Bufo. Born 
does not find that the nucleoli ever give rise to chromosomes, 
and while he ventures no conjecture as td the function of these 
bodies he believes that they “stehen in Beziehung zum in- 
dividuellen Zellleben nicht zur Fortpflanzung.”’ 
According to the observations of Jordan (48) on the newt, 
the chromatin threads “are distinctly traceable through the 
whole history of the germinal vesicle,” although large chro- 
matin granules break loose from the threads at various times 
and pass over into true nucleoli. Janssens has also asserted 
that in the egg of Triton the chromosomes persist throughout 
the entire growth period; but in this egg the chromosomes are 
entirely independent of the nucleoli. 
Lubosch (61) has recently studied the history of the nucle- 
oli in the ovarian egg of Triton with the avowed purpose of 
testing the work of Carnoy and Lebrun. His material was 
preserved and stained in a great variety of ways, and he con- 
cludes that many of Carnoy and Lebrun’s results are due to 
the methods of technique which they employed. As Lubosch 
did not study the very young odcytes, he ventures no opin- 
ion as to the origin of the primitive nucleoli. He states that 
nucleoli are formed periodically at the nuclear periphery, and 
that they then wander towards the centre of the nucleus where 
they undergo one of three modes of dissolution: (1) through 
vacuolization and subsequent differentiation into karyoplasm; 
(2) through distintegration into granules; (3) through transi- 
tion into various sorts of chromatin filaments, some of which 
