AN EXTRA DYAD AND EXTRA TETRAD IN CAMNULA 391 
TABLE 1—Continued. 
Numerical classes of metaphase complexes found in 980 
2 25 dyads 
2 classes of spermatogonia......... ‘ o6idyads 
(11 tetrads + 1 accessory 
3 classes of first spermatocytes.... ) 11 tetrads + 1 accessory + 1 dyad 
(12 tetrads + 1 accessory 
11 dyads 
12 dyads 
13 dyads 
(14 dyads 
4 classes of second spermatocytes.. 
While the chromosome count in the atypical individuals is 
not constant for the gonad, within the subdivisions of this organ 
the organization of the complex does not seem to vary. 
No numerical variations in the metaphase complexes have 
appeared anywhere in these counts within a first spermatocyte 
cyst. With one possible exception in individual 2511, the same 
is true for the spermatogonial complexes. The exception occurs 
in cyst 13, follicle K, of 2511 (table 2). In this cyst it was only 
possible to make two counts. One (pl. 7, fig. 63) clearly gave 
twenty-five dyads, the other complex was interpreted as prob- 
ably consisting of twenty-six dyads; I am not sure enough of the 
interpretation, however, to consider this cell an exception to what 
appears to be arule. In the case of the spermatogonia and the 
first spermatocytes, then, no diversities in the chromosomal 
organization have been found within the cyst in the animals so 
far examined. The counts are always the same for all the cells 
of a cyst of either of these generations. 
Similarly, as an examination of the data given above for the 
aberrant animals will show, the organization of the second sperma- 
tocyte chromosome groups is typically consistent within the cyst. 
Since the accessory passes undivided to one pole at the first 
3 The telophase cell illustrated in tigure 108, which has one less dyad than the 
other cells in the cyst, is not necessarily an exception to the rule of constancy in 
number for the cyst, as the missing element might have been pulled out of place 
by the microtome knife. 
