34 BOTANICAL GAZETTE [JANUARY 
disappearance of the nuclear membrane; there are also one or 
two small nucleolar bodies which remain through the metaphase 
of the heterotypic division and are sometimes observed on the 
homotypic spindle. . 
This papillate appearance of the nucleolus may be interpreted 
in quite another way, namely, as a process of chromatin budding 
from the nucleolus. CarpirF (5) figures nucleoli with similar 
papillae in young spore mother cells, and suggests that a papilla 
may represent the beginning of a chromatin thread formed from 
the nucleolus. Miss NicHots (32), in a study of several species of 
Sarracenia, concludes that the nucleolus of the pollen mother cells 
elaborates the chromatin, and figures nucleoli with small bodies 
attached, which represent the chromatin emerging from the nucle- 
olus. DarwinG (7) describes the budding of chromosomes from 
the nucleolus in the prophase of the heterotypic division in Acer 
Negundo. In the somatic nuclei of the root tip of Phaseolus, 
WaceER (43) describes the nucleolus as being connected with 
suspending fibers along which the chromatin from the nucleolus 
passes. These fibers become much thickened with the accumula- 
tion of chromatin and finally break up into chromosomes. Wi 
the loss of chromatin the nucleolus shrinks, becomes detached 
from the chromosomes at the metaphase, and finally disappears. 
The conclusions of WAGER, however, are disputed by MARTINS 
Mano (26), who made a similar study of Phaseolus and concluded 
that the chromosomes are not of nucleolar origin. He advances 
this interpretation: at the telophase certain portions of the chro- 
mosomes are drawn out into threads which anastomose and form 
a chromatic reticulum. In the following prophase the reticulum 
gradually assumes the form of bands with connecting fibers; the 
bands contract and ultimately break up into chromosomes. The 
appearance that WAGER describes as “suspending fibers’? MARTINS 
Mano interprets in another way. The nucleolus is formed inde- 
pendently from nucleolar substances, but in close contact with 
chromatin elements. When the perinucleolar vacuole is formed, 
there is a consequent repulsion of the nuclear reticulum; certain 
parts of it remain attached to the nucleolus by reason of the elas- 
ticity and viscosity of the chromosomes. Ii the nucleolus furnishes 
