482 D. H. WENRICH 



and 8. In cell F chromosomes 7 and 9 show the constriction, 

 while it is not apparent in chromosome 8. Again in cell G 

 chromosome 9 did not reveal the constriction as did chi'omosomes 

 7 and 8. All three show evidences of a constriction in cell C. 



In connection with this synaptic point, as already mentioned, 

 there is a small plasmosome-like appendage, or chromomere- 

 vesicle (marked c in the figures), which seems, in the earlier 

 stages at least, to be as constant in its occurrence as is the con- 

 striction just described. It disappears in the later tetrad stages 

 as such structures usually do. Similar appendages are occa- 

 sionally seen attached to the synaptic points of chromosomes 

 7 and 8, as is indicated for the former in cell D and for the 

 latter in cell A, but their occurrence on these chromosomes is 

 rather infrequent. 



It will be noticed that only one appendage is to be seen on a 

 smgle chromosome in the figures on plate 1. In earlier stages, 

 however, there are two such bodies as is indicated in figures 2, 

 3, 4, 6 7, 8, and 9, plate 3. Figure 5 shows the two partially 

 fused together and many times they appear to be entirely fused 

 at these stages. It could not be determined whether the single 

 appendage in plate 1 and in figures 10 to 14 on plate 3 repre- 

 sent two fused together, or whether one of them disappears 

 before the other. The latter possibility is suggested by a con- 

 stant difference in size in all cases where two are in evidence 

 and by the fact that the single ones in figures 10 and 11 do not 

 appear to be equal in bulk to two such as are shown in figure 9. 

 In figures 12, 13, and 14, they appear larger, but these figures 

 are taken from sections from another individual, which fact may 

 account for their larger size. That these structures are con- 

 stant elements of this pair of atelomitic chromosomes is well 

 illustrated by the spermatogonial telophases shown in figures 7 

 and 8. In each case the 'vesicle' is attached at the apex of a 

 V-shaped chromosome with a marked disproportion between the 

 lengths of the arms, comparable to that seen for chromosome 9 

 on plate 1. In figure 8, the smearing process has resulted in a 

 slight distortion of one of the atelomitic chromosomes (at the 

 left) to which an appendage is attached. It seems fairly safe to 



