Embryology. 



133 



XI. 



XII. 



VI., VII. The V-shaped filaments are splitting longitudinally ; their structure of fine 

 granules of chromatin is apparent in VII., which is more highly magnified. The 

 conjugation of the pronuclei is apparently complete in Vll. The attraction- 

 spheres and achromatic spindle, although present, are not depicted in IV., V., 

 VI, and VII. 



VIII. Equatorial arrangement of the four chromatin loops in the middle of the 

 now segmenting ovum : the achromatic substance forming a spindle-shaped 

 system of granules with fibres radiating from the poles of the spindle (attraction- 

 spheres); the chromatin forms an equatorial plate. (Compare Fig. 36 G.) 



IX. Shows diagrammatically the commencing separation of the chromatin fibres 

 of the conjugated nuclei, and the system ot fibres radiating from the attraction- 

 spheres. (Compare again Fig. 36 G.) f.c. t polar circle ; e.c., equatorial circle ; 

 e.g., central particle. 



X. Further separation of the chromatin filamentm. Each of the central particles 

 of the attraction-spheres has divided into two. 



XI. The chromatin fibres are becoming developed into the skeins of the two 

 daughter-nuclei. These are still united by fibres of achromatin. The general 

 protoplasm of the ovum is becoming divided. 



XII. The two daughter-nuclei exhibit a chromatin network. Each of the attraction- 

 spheres has divided into two, which are joined by fibres of achromatin, and con- 

 nected with the periphery of the cell in the same way as in the original or parent 

 sphere, III. 



