1090 
t 
rations can easily be washed with water and stained, for example, 
with Brillantblau extra griinlich. The nuclear network, the nuclear 
plate or its halves which all fall over during the action of chromic 
acid are then stained a fine blue whilst the siliceous skeleton is not 
stained. I will not enlarge on the method followed. I have already 
earlier stated the advantages which it possesses and which must be 
borne in mind in its appheation *). 
Like other Diatomaceae Eunotia major has but one nucleus, 
situated in the centre and surrounded by eytoplasm, which sends out 
strands in various directions. As seen from the side of the belt it 
shows an oval shape and seen laterally it is round. It is provided 
with a membrane and consequently shows a sharp outline. The 
nuclear network consists of grains which are united by threads of 
protoplasm. In the centre of the nucleus is the nucleolus. The latter 
dissolves in chromic acid more readily than the network. Special 
filamentous organs, such as occur in the nucleolus of Spirogyra, I 
have not been able to distinguish and to separate by the use of 
chromic acid in the case of Eunotia. The nucleolus agrees with that of 
the higher plants. 
The cells in which karyokinesis is about to occur are broader than 
the others and possess four large flap-shaped chromatophores. When 
the cells are viewed from the side of the belt, the nucleus is seen 
in the midst of the four chromatophores, two of which lie in the 
epitheca and two in the hypotheca. When a cell has divided, two 
chromatophores lie in each daughter-cell. These change their shape 
and position. They become twice as long and place themselves 
opposite each other in the epitheca and the hypotheca. A constriction 
then occurs in the middle and ‚finally each chromatophore has divided 
into two. This process, the division of the two chromatophores, there- 
fore precedes the division of nucleus and cell. 
The first phenomena of karyokinesis show agreement with those 
observed in other plants. The nuclear network becomes more and 
more roughly granular in appearance. In a number of places it 
comglomerates and forms lumps, which unite into larger masses 
which more or less resemble short threads. I have not been able 
to determine the number of these thicker parts in the network. 
They always remain united to each other by slender connections. 
1) Ueber den Nukleolus von Spirogyra. (Bot. Zeitung. Jahrg. 56. 1898. Abt. I. 
p. 199). — Ueber das Kerngeriist. (Bot. Zeitung. Jahrg. 57. 1899. Abt. 1. p. 155). — 
Ueber die Karyokinese bei Oedogonium. (Beih. z. Bot. Centralbl. Bd. XXIII. 1908. 
Abt. I. p. 138 ff). — Ueber die Kernstructur und Kernteilung bei Closterium. 
(Beih. z. Bot. Gentalbl. Bd. XXVII. 1912. Abt. I. p. 414). 
