34 



DEVELOPMENT OF THE FKOG'S EGG 



[Cii. IV 



If a series of sections be made throiig-li the egg at different 

 stages ill the i)roeess of eleavage, we should see that prior to 

 the division o( cdvh bhistoniere the nneknis had divided into 

 two jiarts. This takes phice by the ordinary process of indirect 



D 



G H 



Fir.. 13. — Seg'ineutation of egg (two, eight, sixteen, and thirty-two cell stages, after 

 ^I. Sehultze). as seen from above. A. Two-cell stajre : Ijesiinning of second fur- 

 rows. B. Eiiiht-eell stage, with cross-furrow. C, D. F, G. Sixteeu-cell stages. 

 E. Eight-cell stage (regular type). H. Thirty-two-cell stage. 



or karyokinetic division. Half of the chromatin passes to one 

 pole of the nuclear spindle, and the other half to the other pole. 

 As the spindle elongates, it carries with it the surrounding pig- 



