On the Dimegalous Sperm and Chromosomal Variation of Euschistus, etc. 131 
A Word as to the method of coimting. Only those cases were selected 
where all the chromosomes lay in the plane of the section and were so se- 
parated as to be readily coimted. The chromosomes were drawn from 
polar views of equatorial plates, then counted on the drawings. No case 
was inclnded where there was a reasonable doubt as to their number. On 
acconnt of the large number of counts made, probably the largest number 
up to this time on any one species, a number of errors may have been made. 
But the material is exceptionally favorable for such an examination on . 
account of the small number and relatively large size of the chromosomes. 
Then my attitnde of mind was fairly objective, far 1 had no wish to prove 
either constancy in number or inconstancy, my intention being simply 
to learn how much inconstancy there might be^). 
The follo’W'ing table presents the results of these counts for six festes 
of Eiisckishis sp. The numbers of the particular festes are given on the 
left, while in the vertical columns are stated the number of cells counted 
arranged according to the number of separated elements irrespective of 
the valence of such elements. Thus the bivalent diplosome of the second 
spermatocytes is counted as 1, just as is each bivalent autosome of the 
first spermatocytes. The starred chromosomal numbers on the upper 
line represent the normal or usual condition. 
Testis 
Spermatogonia ' 
First Spermatocytes 
Second Spermatocytes 
13 
*14 
15 i 
*8 
9 
10 
11 i 
6 
*7 
8 
9 
no. 103 
10 
45 
1 
51 
1 
no. 105 
22 
3 
47 
no. 106 
10 
43 
3 
1 
44 
no. 120 
4 
4 
67 
26 
3 
2 
1 
138 
6 
2 
no. 282 
1 
15 
89 
12 
1 
177 
1 
no. 286 
70 
6 
201 
1 
Summäry 
: 1 
39 
4 
436 
50 
4 
2 
3 
658 
9 
2 
Wc may now consider the details for each testis by itself. 
Testis no. 282. 
The fable shows that in each of 15 instances exactly 14 chromosomes 
were found in the spermatogonia. In a 16th cell only 13 were seen, which 
1) In my paper of 1906 I found that tlie spermatogonia “show in most cases 
14 chromosomes .... But in one case there were clearly 15 ... . And now I find 
two clear cases each with 16 chromosomes”. I have reexamined these cases of 16 chro- 
9 * 
