368 



Conjugate 



cell is the pinching in of the two chloroplasts at a point about a third the 

 distance from the middle to the extremity, and that the division of the 

 chloroplasts is entirely distinct from that of the cell. This constriction occurs 

 altogether inside the plasmatic membrane of the cell and is probably the 



Fig. 231. A 1>, stages in the division of Closterium Ehrcnbergii Menegh., x 272 (after Lutman). 

 E, tranverse section of Cl. moniUfenim (Bory) Ehreub., showing ten peripheral ridges on the 

 chloroplast and one of the axial row of pyrenoids, x about 800 (after Lutman). F I, 

 stages in the division of Mesotsenium caldariorum (Lagerh.) Hansg., x 900. n, nucleus; oJ, 

 oil globules; py, pyreuoid. 



constriction of a membrane which forms the outer layer of the chloroplast. 

 No nuclear changes are visible at this stage. During the time the two 

 chloroplasts are dividing, the nucleus divides and after reconstruction of the 

 daughter-nuclei, the latter can be seen moving out to the surface of the 

 chloroplast and making their way along the convex margin of the cell to their 



