MENDELIAN RATIO AND CHROMOSOMES 489 
OBSERVATIONS 
1. Spermatogonia 
Thanks to the accuracy of Sutton’s drawings, but little re- 
mained in this stage for me to do. He found that the entire 
complex could be separated into two groups, one containing 
six small chromosomes and the other seventeen larger ones. Ex- 
amination shows that his group of six small chromosomes is 
composed of five of about equal size and one decidedly larger. 
Two of his four spermatogonial figures show this clearly; in his 
first paper (00), plate 33, figure 23, the largest chromosome of the 
small group, is apparently attached to the end of a member of 
the large group; in the second paper (’02) figure 2, the pair marked 
‘y’ are clearly unequal in size. In figure 1 the chromosomes 
are present in oblique or end views, and in figure 3 the real size 
of either ‘2’ or ‘7’ may be concealed by the overlying chromosomes. 
To appreciate properly the weight of this evidence, we must re- 
member that Sutton believed that they formed pairs, the individual 
members of which were of equal volume. This is true, probably, 
except for the two that unite to form the unequal tetrad. Figures 
1, 3 and 4 of this paper show typical polar views of metaphases, 
with the entire group of twenty-three present, and reveal the 
relative volumes of the six small chromosomes clearly. Figure 
2 shows the six small ones and their relative volumes, although it 
does not contain the entire complex. 
Polar views of complete spermatogonial complexes of Arphia 
also show a possible separation into a group of small and a group 
of larger chromosomes, with the difference here that the small 
group consists of but four members while the larger one has nine- 
teen. Close observation of the four small chromosomes shows 
that three of them are of practically equal volume and the re- 
maining one (figs. 5 and 6, a) is slightly smaller. 
2. Growth period and earlier diffuse stages 
These observations are based principally upon Arphia, for 
while the nuclei of Arphia and Brachystola are practically iden- 
. tical in size those of Arphia are much clearer, partly owing to 
