1912] 



YAMANO UCHI—C UTLERIA 



473 



* 



During the development of the zoospore mother cell, while 

 these nuclear divisions have been taking place, the cell wall remains 

 apparently unchanged, except at the top of the mother cell, where 

 there has been a gradual increase in thickness, which culminates 



at the time of cleavage. 



As the 





zoospore primordia are com- 

 pletely formed, the top of the 

 cell wall begins to swell (fig. 

 200), then disintegrates into 

 lamellae, with lacunae between 

 them (figs. 201, 202). Finally 

 the disintegrating lamellae of 

 the cell wall become completely 

 disorganized, so that a pore is 

 formed at the top, and through 

 this the zoospores escape after 

 maturity. 



The zoospore in free swim- 

 ming condition is oval (fig. 14, a) , 

 and usually contains more than 

 20 plastids. Associated with 

 one of the plastids, which lie 

 inside the plasma membrane, 

 there is a red pigment spot, in 





M 





■ 



i 



*r 



m 



* r 



* • 



, 



;%" 



*" 



a 





\ 





a 



\ 



. 



a- 



S 



\ 



•- 



! 



\ 



d 



b 



Fig. 14. — Aglaozonia reptans: zoo- 

 spores sketched from living material; a, 



Close association with which tWO i n f ree swimming condition; a', begin- 

 cilia of different lengths are at- ning to be quiescent and spherical ; a", in 



tached, the 



longer 



one 



being 



quiescent condition; the size varies ac- 

 r i- * \ , " " "7 V *i — "o cording to the number of nuclear divi- 



airected toward the anterior sion s within the mother cell; a, a', and a' 



end, about three times the are the products of three divisions (out- 

 length of the zoospore, and a put of 8 zoospores) ; 6, from four divisions 

 <;Vir>rt ^~ ~ 4. j- • ./ (output of 16 zoospores); c, from five 



short one extending in the oppo- ^Lns (output of 32 zoospores). 

 site direction about one and one- 

 third the length of the zoospore. The length of the zoospore is 

 2 . 5 M when the output of the zoospores in a cell is 8 (figs. 14, a', 

 a ), 18.7 fi when the output is 16 (fig. 14, b), and 10.5 \i when the 

 output is 32 (tig. 14, c ). 



2 



