THE VITAL PHENOMENA OF THE CELL 



211 



lobulated nuclei are frequently seen, and yet fragmentation does 

 not appear to occur in these cases, so that the tabulation must not 



A 



FIG. 103. Tvadescantia virginica. Cell nuclei of older internodes undergoing direct 

 division (after Strasburger, Fig. 193) : A from life ; B after treatment with acetic-acid- 

 methyl green. 



be considered to be the commencement of direct division. It is 

 apparently connected with metabolic processes in the nucleus (cf. 

 what is said upon the subject in Chapter VIII,). 



Nuclear multiplication 

 by direct division occurs 

 also amongst Protista ; 

 it is seen with especial 

 frequency in the group 

 of Acinetae, of which the 

 Podophrya gemmipara 

 (Fig. 104), described on 

 p. 229, is an instructive 

 example. 



3. Endogenous Nuclear 

 Multiplication, or the 



Formation Of Multiple FIG. 104. Cell-budding. PodopTirya gtmmipara 



Nuclei with t)uds *" Hertwi & ^ l *9i/i Fi &- 21 )-* bud* 



which are becoming detached and developing into 



A third, very different zoospores b : N nucleus. 



