134 ETHEL NICHOLSON BROWNE 



number of these smaller bodies seems to be quite constant, three 

 pairs at one end and two at the other (fig, 93) . In the very late 

 prophase, after the chromosome is on the spindle, it is still loosely, 

 organized, and its several characteristic components may be 

 seen (fig. 94). In full metaphase the chromosome becomes more 

 compact, and, as I have described, usually consists of a central 

 mass with a small component at each side. Occasionally one 

 finds the chromosome in metaphase with two small elements on 

 one side and one on the other (fig. 95). In early anaphase, the 

 smaller components appear as knobs or strands projecting at 

 an angle from the main mass (figs. 89, 92 B and 96). 



In the second division, the peculiar X Y pair take up the usual 

 position in the center of the spindle surrounded by a ring of 

 12 other chromosomes (figs. 97, 98 A, B, C and 99 A, B). In the 

 group are the double chromosomes, lying on the spindle with 

 the split, which was in evidence in the first division, on the equa- 

 torial plane, marking the line of separation of its components. 

 There is also present in this division an asymmetric quadripar- 

 tite chromosome, similar to the d-chromosome described by Wil- 

 son ('11) in Nezara (figs. 97, 98 C and 99 B). The appearance 

 of the X chromosome in the second division is somewhat vari- 

 able, owing probably to the way it has been cut in the section ; 

 it most often appears as a central mass with small masses hanging 

 down from each end, Y being usually attached by a fiber to one 

 of these ends (figs. 98 B, 99 A and 100 B). The fact that its 

 shape is not dependent on the presence of Y is shown by its re- 

 versed position in some cases (fig. 100 E). The connection be- 

 tween the different parts of X is in many cases not evident, but 

 this may be due to the thinness of the thread or to its being just 

 without the plane of section (fig. 97 and 100 C, D). The char- 

 acteristic ring figure with X Y in the center is seen in polar views 

 (figs. 101 and 102). Among the chromosomes in the peripheral 

 ring are the two large ones which appeared double in side views ; 

 their double nature usually does not show now or is only indi- 

 cated by a notch in the side. Owing to the peculiar shape of X, 

 detached pieces of it often appear in polar view, and since these 

 are about the same size as Y, it is impossible to tell which these 



