500 D. H. WENRICH 



also show this difference. In figures 10 and 11, the vesicle that is 

 present does not appear to be any larger than the largest one in 

 figure 9, and this fact lends support to the idea that the smaller 

 one disappears early instead of fusing with the larger. The 

 cases shown in figures 12, 13, and 14 are from section of another 

 individual and can therefore not be discussed in this connection. 

 If we assume, then, that the pair of chromatids to which vesicles 

 are attached in chromosome 9, cells E and F, and in chromosome 

 7, cell D (plate 1), for example, represent one of the conjugants, 

 then the evidence seems clear that a reductional division should 

 take place. 



On the other hand, if it ber assumed that the two vesicles have 

 fused to form one, then one of them must have broken loose 

 from its former attachments when the pairs of chromatids sepa- 

 rated, as they do in the tetrads, whether or not the separation is 

 along the primary or the secondary plane. When it is consid- 

 ered that these structures are eventually destined to disappear 

 in the later tetrad stagles, as shown by the fact that many of the 

 tetrads observed in the stages represented by cells C to E (plate 

 1) do not show any vesicles, "the assumption made above does not 

 seem unreasonable. But, if these vesicles are to be regarded 

 as shifting in their attachments, then it might be objected 

 that such structures offer uncertain bases for deduction. On 

 this account, deductions made on the basis of the behavior of 

 these vesicles in the later tetrad stages may have to be con- 

 sidered as not entirely satisfactory. Nevertheless, because of 

 the constancy of occurrence of these bodies throughout the 

 pachytene stages, and the constant difference in size between 

 them, as already mentioned, the most reasonable conclusion 

 would appear to be that the one remaining vesicle, as found 

 in plate 1, and figures 10 and 11 on plate 3, is attached to one 

 conjugant and that therefore, a reductional division is fore- 

 shadowed. 



We may attack this problem of reduction in the atelomitic 

 chromosomes from a different angle. In chromosomes 2, 4, and 

 6, plate 1, a probable behavior of telomitic chromosomes was de- 

 scribed which paralleled that of chromosome A in Phrynotettix, 



