COMPARED WITH THOSE OF ANIMALS. 



59 



Ttus as soon as tlie first inflection can be traced in the 

 walls of the cell, the nucleus begins to undergo subdivi- 

 sion, and when the cell is finally divided, each cavity con- 

 tains a portion of the nucleus. These two new cells with 

 their contained nuclei again subdivide in a similar manner, 



15 



Development of cartilage cells. A, original cell ; B, the same beginning to 

 divide ; C, tlie same, showing complete division of the naclens ; F, the same with 

 the halves of the nucleus separated ; G, and H, continuation of the same pro- 

 cess; by continued cleavage in the same direction, and the ultimate produc- 

 tion of a longitudinal series of ceUs. — Carpektee. 



producing a filament or row of cells, when the division takes 

 place in one direction, and a plane or solid mass of them, 

 when the cleavage takes place in two or more directions. 



3. Formation of cells by gemmation or budding. 



This is well seen in Conferva glomerata. Fig. 13, which in- 

 creases, not only longitudinally by the repeated subdivision 

 and expansion of the cells at the extremity of its filaments, 

 but laterally by a process of outgrowth or budding. A cer- 



