THE NUCLEI OF UROLEPTUS MOBILIS 



325 



e. The amphinncleus. The two pronuclei unite in a region of 

 the body slightly anterior to the geometrical center. There is 



Figs. 71 and 72 Enlargements of the wandering pronuclei and 'attraction 

 spheres.' X 1500. 



some evidence that the stationary nucleus advances to meet the 

 migrating nucleus, since the former is formed either in the center, 

 or posterior to the center, of the cell (figs. 64, 68, 69 and 76). 



