3 
nucleolus as mostly spherical and homogeneous; in some 
cases it shows an irregular, very aberrant form. 
Escoyez states that during the prophase of karyokinesis 
thicker parts arise in the network which shows a looser 
structure. Finally 30 to 40 chromosomes are formed which 
resemble rodlets. 
The chromosomes arise directly from the network which 
does not first form a spirem. The nucleolus plays no 
morphological part in the formation of chromosomes. Its 
shape undergoes modification and finally it completely 
dissolves. Escoyez states that the nuclear spindle penetra- 
tes into the nuclear-cavity and that the chromosomes 
subsequently form an equatorial ring. Then longitudinal 
splitting takes place, the chromosome halves take up a 
position near the two poles of the nuclear spindle, which 
are found near the chromatophores. They crowd together 
into plate-shaped bodies. Later they again become visible 
to the number of 30 to 40. Gradually a network forms 
which corresponds with that of the resting nucleus. Escoyez 
says that the nucleolus is first a small body which gradu- 
ally increases in size. Its formation is independent of the 
chromosomes. 
The object of Escoyez's investigation was not only to 
control Miss Merriman's results, which diverge greatly 
from those generally obtained in karyokinetic inquiry, but 
he wished also to answer the question whether Zygnema 
so far as the nucleolus and karyokinesis are concerned, agrees 
with Spirogyra where according to Escoyez J. Berghs)) 
has established that the twelve chromosomes arise exclu- 
sively derived from the nucleolus. As is already evident 
from the above, Escoyez's investigation yielded negative 
results on both points. His results differ widely from 
1) J. Berghs, Le Noyau et la Cinèse chez le Spirogyra. Extrait de 
la Revue “La Cellule”, t. XXIII, ler fasc. 1906. p. 55—85. 
1* 
