ORILLA STOTLER WERNER. 



graduated series. Only twenty-two of these are of sufficient size 

 to permit their being paired. The remaining twenty- four are 

 small and so closely graduated in size that it is impossible to 

 pair them with any degree of certainty. 



The nine pairs of short rods and the twenty-three pairs of globe- 

 shaped chromosomes are remarkably constant in shape during the 

 progress of prophase from the time they are discernible as individ- 

 ual bodies until they enter the equatorial plate in metaphase. 

 Here they mass together to such an extent that frequently they 

 are no longer distinguishable as individual bodies. But even in 

 this phase it frequently happens that they may be seen in their 

 characteristic forms. 



There appear to be seventy-seven chromosomes in the cells of 

 the female (Figs. 8-22, 37-42). The longest of these is a large 

 unpaired body, larger than any of the other chromosomes, and 

 on account of its size, in most cases, easily distinguishable from 

 the other chromosomes (Fig. 3742, W). In cross section it is 

 large at one end and taper at the other. In the earlier stages of 

 mitosis it is a more or less bent rod, seeming to accommodate it- 

 self to the other nearby chromosomal regions and also to the 

 nuclear wall (Figs. 8, 10, W). In the late prophase and the early 

 metaphase it continues to be a more or less bent rod (Figs. 9, n). 

 In Fig. 17 it is a rod bent upon itself. Figs. 14 and 22 show it as 

 U-shape while 16, 19 and 20 show it with bendings in different 

 regions. In Fig. 12 it is a rod somewhat foreshortened. It would 

 seem that this chromosome possesses a great degree of flexibility 

 throughout its length which permits its bending in various ways. 



The next largest chromosomes in the cells of the female take 

 at times the form of curved rods but more frequently are of 

 J-shape (Figs. 8-22, 37-42 ; 38w, 38Z). Whether they are gonial 

 mates or not it is difficult to say. Theoretically, as will appear 

 later, they should not be. From their size and their J-shape 

 one would suppose that at least one of them is a homologue of 

 the 38*3 in the cells of the male. The other might be of the nature 

 of a w-chromosome. 



Slightly shorter than these are two large curved rods (Nos. 37) 

 one of which in prophase and early metaphase quite frequently 

 takes the form of an S (Figs. 9, 17). The members of this pair 



