64 The Chromatin in the Development of Hybrids 



PLATE IV. 



Fig. 29. Anaphase of the first cleavage of a Fundulus hybrid egg. The 

 small Menidla chromosomes introduced by the sperm are grouped to the 

 right. 



Fig. 30. Anaphase of the first cleavage of a Menidia hybrid egg. Here 

 the long Fimdulus chromosomes have been introduced by the sperm and are 

 grouped on the right in the spindle. 



Fig. 31. Half of an anaphase spindle of the second cleavage of a Men- 

 idia hybrid. The short and the long chromosomes are grouped to the 

 right and left respectively. (^ Fundulus. 5 Menidia. 



Fig. 32. Late metaphase and late anaphase of cells from middle cleavage 

 of a Menidia hybrid egg. In the latter the long chromosomes extend for a 

 considerable distance along the spindle fibres while the short ones are 

 nearer the poles and form a band across the spindle, c? Fundulus. 5 

 Menidia. 



Fig. 33. Late anaphase of a cell from middle cleavage of a Menidia 

 notata egg. All the chromosomes are short. There are no long straggling 

 chromosomes as in the hybrid cells (Fig. 32.) See also Figures 22 and 2G. 



