GO The Chromatin in the Development of Hybrids 



PLATE II. • 



Figs. 8, 9 and 10. Types of abnormal " blastopore " closure in the 

 Menidia hybrids. 



Fig. 11. Late anaphase of the first cleavage of a normal Fundulus heter- 

 oclitus egg. All of the chromosomes are of the long- type. 



Fig. 12. Anaphase of the first cleavage of a normal Menidia notata egg. 

 All of the chromosomes are of the short type. 



Fig. 13. Chromosomes of Fundulus heteroclitus and Menidia notata 

 drawn io the same scale. Both are taken from the spindle shown in Fig- 

 ure 14. 



Fig. 14. Anaphase of the first cleavage of a Fundulus hybrid egg. To 

 the right in each half of the spindle occur only the short chromosomes; 

 to the left, only the long ones, c? Menidia. 5 Fundulus. 



Fig. 15. Anaphase of the first cleavage of a Menidia hybrid. To the 

 right are all long chromosomes; to the left, all short ones. J' Fundulus. 

 5 Menidia. 



Fig. 16. Metaphase of first cleavage of Fundulus hybrid. The larg'e 

 chromosomes to the right. J' Menidia. 5 Fundulus. 



Fig. 17. Metaphase of the second cleavage of a Menidia hybrid. The 

 long chromosomes to the right. ^ Fundulus. 5 Menidia. 



Fig. 18. Half of an anaphase spindle of the second cleavage of a Menidia 

 hybrid. All of the long chromosomes are to the left, c? Fundulus. 

 2 Menidia. 



