i8o 



MARINE BIOLOGICAL LABORATORY. 



nucleus. This polar flattening of the nucleus goes on 

 until the nucleus presents the appearance shown in 

 Fig. 4. 



Space only forbids the illustration of the further 

 changes, but it may be easily imagined that when this 

 flattening of the nucleus is continued, the whole solid 

 contents of the nucleus are reduced to a single flat sheet 



M-^-,V-^ 



Fig. 3. — Loligo. 



iV Nucleus. X Nucleolus (?) 



as it were, as shown in Fig. 5, forming the equatorial 

 chromatic "plate." The spindle then, as its history 

 clearly indicates, consists of two cones with their bases 

 turned toward each other, and with their apices in the 

 archoplasmic centres, as was first pointed out by van 

 Beneden. 



