AN EXTRA DYAD AND EXTRA TETRAD IN CAMNULA 385 
Hence no attempt was made to get a complete series of counts. 
The results in fifteen cysts are as follows: 
First spermatocytes 
Follicle A | 18 metaphases: 11 tetrads + 1 accessory + 1 dyad (figs. 7 and 8). 
Cyst 1 1 metaphase: 10 tetrads + 1 accessory + 3 dyads (fig. 10).? 
Follicle B 
Cyst 3 
9 metaphases: 12 tetrads + 1 accessory (figs. 1, 2, 3). 
1 anaphase: 12 dyads + 138 dyads. 
Gai 6 metaphases: 11 tetrads + 1 accessory + 1 dyad. 
Follicle D 
5 1m : 
Cyst 10 7 metaphases: 12 tetrads + 1 accessory. 
Follicle C } 
Follicle E \ 
cee 5 metaphases: 11 tetrads + 1 accessory + 1 dyad (fig. 9). 
Follicle F \ 
Grane 2 metaphases: 11 tetrads + 1 accessory + 1 dyad (fig. 6). 
Cyst 7 6 metaphases: 12 tetrads + 1 accessory (fig. 4). 
Follicle H 
Cyst 8 5 metaphases: 11 tetrads + 1 accessory + 1 dyad. 
J 
Follicle G } 
Follicle I 
Cyst 9 
} 3 metaphases: 12 tetrads + 1 accessory (fig. 5). 
(In the above complexes the accessory or sex chromosome is, 
of course, a dyad; it is listed separately from other elements of 
like valence throughout the first spermatocyte statistics given in 
this paper because of its differential character, it being always 
easily recognizable.) 
2 In this cell the two dyads of tetrad number 10 either failed to synapse or 
divided prematurely. One of these dyads has gone to one pole, while the other 
is still in the equatorial plate. If both had gone to the same pole as the small 
dyad (s), a second spermatocyte cell containing two extra dyads would have 
resulted. If both had gone to the opposite pole, a second spermatocyte cell 
containing a large extra dyad would have been the result. In either case we 
would have had also a second spermatocyte cell lacking dyad number 10. 
