PLATE 4 



EXPLANATION OF FIGURES 



17 Examples of octad rings in late prophase showing various aspects during 

 the process of opening out. These are arranged somewhat in the order of 

 progress from a to k. 



18 Lateral view of first sperraatocj'te metaphase, class 6. One octad ring, 

 and accessory chromosome at one pole. 



19 Three examples of extended V's, such as shown in Photo Y. 



20 Lateral view of first spermatocyte metaphase of class 5 with the V por- 

 tion of the smaller octad going to same pole as the accessory chromosome. Ten 

 free chromosomes. 



21 A complex of a first spermatocyte of class 6 in which the one octad is a V. 



22 Two first spermatocyte octads from one cell. 



23 A complex of H. pratensis in which the hexad is similar in shape to that 

 of Anabrus. 



24 A complete complex of Hesperotettix viridis, class 3, in which the octad 

 has opened at one side, simulating the appearance of the hexad in Mermiria. 



25 The three multiples from a complex of class 4. 



26 An entire complex of class 3, from the same animal as in figure 24. 



27 A representative complex of class 5 with one V. 



596 



