590 



A. A. W. HlJBllECHT. 



origin to the union of the male and female pronncleus) at so 

 early a moment are not revealed by my preparations, and we 

 cannot for the present come to any sound conclusion as to 

 which of the two modes of formation of the trophoblast is 

 the more arcliaic one. 



Recognising that the definite answer to this question can 

 only be given when a number of new observations will be at 

 GUI- disposal, I may still be allowed to call attention to the 

 fact that in diMleopithecus the spot where the polar bodies are 



Tkxt VUi. '.]. 



Galeopithecus. A series of six sections through a cleavage stage 

 just preceding the formation of the second pair of cleavage- 

 cells. In C karyokinetic figures indicate tliis. In B — E the 

 pohxr bodies are visible. Apparent tropholjlast nuclei are 

 situated pei'ij)herally. 



applied against the egg (see Text-rig. 8 B — E) remains without 

 troplioblast nuclei somewhat longer than other parts of the 

 egg's surface. The question presents itself — supposing the 

 process is more piimitive in Galeopithecus — whether this 

 particularity might have led (in such mammalian genera that 

 should be considered as phylogenetically younger) to the 

 arrangement which lias induced van Beneden, Duval, and 

 Assheton (in his later publications) to consider the cleavage- 

 process of those mammals as revealing epibolic characteristics. 

 In case this question will later have to be answered in the 



