ORIGIN OF THE CENTROSOME. 



277 



some way, however, they may begin to multiply by the process 

 of caryokinetic division, when the centrosome makes its appear- 



Flg. "i. — The pigment cell of E SOX lucius, showing the clear centrosome area C; NN, nuclei. 

 By the application of Golgi's method, as modified by Cajal, the nerve endings are well brought 

 out. The cell is innervated on both sides of its surface. At d, d', the nerve filaments on one 

 side are seen boring through the whole thickness of the cell and innervating the other side. — (After 

 E. Ballowitz.) 



ance, and takes an active part in the separation of the chro- 

 matic elements. The division over, the cell assumes a quies- 

 cent state once more, and we no longer recognize a centrosome 

 or a radial arrangement of the cytoplasmic threads. 



ct 







Fig. 4. — (a) Brown pigment cell of Sargus annularis. The clear streak (O ninning through 

 the length of the cell is the elongated centrosome or " Centralstab " (Zimmermann). 



{b) Yellow pigment cell of Sargus annularis. C, the rod-like centrosome, with parallel fibrils 

 proceeding from it. JV, the nucleus — (After K. W. Zimmermann.) 



